There are many companies who offer DNA analysis for purposes of discovering family members. Deciding on getting tested is a complex decision. Let me help you decide.
As you might infer from the image above, I feel DNA testing is over-rated for genealogical research. There is a place for it, as long as you do not expect too much. TL;DR jump to “Should I get a DNA test?“
What’s out there
For $99, 23andMe offers the “best DNA kit with the most comprehensive ancestry breakdown and 30+ trait reports. – 80+ personalized reports – Ancestry percentages (to the 0.1%) – 2000+ geographic regions” They claim that you can “Discover where in the world your DNA is from across 2000+ regions — in some cases, down to the county level.” 
There are several other players in this market, however my only (semi-)direct experience is with Ancestry.
Normally about the the same price as 23 and Me, often on sale for around $59, “AncestryDNA® ethnicity estimates are now more precise than ever. We’ve applied our latest cutting-edge science to AncestryDNA® ethnicity results. Take a look at your updated results and get a more precise picture of just where your ancestors came from.” 
My Mother and Father purchased the Ancestry DNA test several years ago, after my Father had done years of collaborative genealogical research.
What you can learn
There are some sensational stories out there of people discovering family secrets through a DNA test. These are fairly rare. Most of us have a “no, duh, my family came from England and Scotland” kind of response. The “1%” results from Africa of Asia don’t say anything except “people traveled in the past!” My Father’s results matched him with four people characterized as “Close Family–1st Cousin,” three first cousins, two second cousins, and 43 third cousins and many hundreds listed as “4th–6th Cousin.” We know all of the “Close Family–1st Cousin” listed. One is my Father’s 1st cousin, one is a grandson, and the other two are nieces. My Father knew the parents of the two second cousins identified, one is actually a first cousin once removed – still good result.
It was great to look at some of the family trees maintained by these DNA matches, however the knowledge gained was minimal, since we shared at most, 1/4 of their great grandparents. Most of the common ancestors listed were the best-documented in our own tree – notably, they were usually the only one with photographs, many of which came from our immediate family!
Once you get to the “3rd–4th Cousin” there was little learned from their trees. Either there was no apparent common ancestor, or no new details about those we did share. At this level, our common ancestors would have died in the early to mid 1800s, meaning that there are few details that we don’t already have. Photos were rare until later, and even letters or news articles would have already been shared via closer cousins.
A place to start?
If you have no genealogical research yet done on your family, you can get some clues as to where to start. You will learn general information about where your ancestors lived. You may also be able to connect with cousins you otherwise might not know, and they may have done much family research that will be of interest to you. As we’ve already discovered, distant cousins rarely have any unique information on our common ancestors.
In the process of placing my research on Family Search, I encountered and had correspondence with two of the people in my Father’s “match list” – we connected without the need for DNA tests.
The bottom line is that DNA test are not the best source of this basic information (see why in the next section). The family stories you already have access to are a much richer source to start with, If you know any of your grandparents’ names and places they lived, you can know more definite information about your heritage with my free initial survey than you will learn from a DNA test.
What’s wrong with DNA tests?
The problem with DNA test is that you get half of your DNA from each parent. That makes you “half like” your parents, a “quarter like” your grandparents, and so on. This “so on” in where DNA test fail to give useful information, since the “common” gets cut in half each generation. By the 6th generation, we get 1/64 of our DNA from each ancestor. For our 5th cousins, there is a nearly 70% chance of NO detectable common DNA .
Another study showed that less than half of 4th cousins shared “IBD segments” of “identical by descent” DNA. From that article: “This is important to remember when doing genetic genealogy: if you don’t share segments with someone that doesn’t necessarily mean you’re not related to them.”
While the common test will always find close relatives (who you already know?), there is a significant chance that more distant relatives will not produce a match.
And, as I detailed earlier, getting a lot of “matches ” for distant cousins will tell you very little about who your ancestors are.
Basically, “DNA Ancestry Tests Are ‘Meaningless’ for Your Historical Genealogy Search.”  I include some links to more reading in the footnotes , especially how the analysis is based upon samples from populations that were on the move. “It’s not that the science is bad. It’s that it’s inherently imperfect, an estimation based on how much our DNA matches up with people in other places around the world, in a world where people have been mixing and matching and getting it on since the beginning of human history.”[6-2]
Should I get a DNA test?
If you are concerned about those genetic illnesses or susceptibilities that can be discovered by testing, then yes, with good genetic counseling!
If you want to understand your heritage better, start with traditional genealogical research and use DNA to break through any brick walls you might encounter in those most recent generations.
If you were adopted and have no other way to discover your birth ancestors, then go get a DNA test. Before you read the results, have some emotional support, as there could be sad stories and biological relatives who aren’t as happy as you are about this “discovery.”  This applies to finding estranged family members as well.
Don’t waste your money if you just want the answer to “who am I?” You are not your DNA.
DNA does not make family
Perhaps the biggest consideration is what you want to learn about who you are. DNA has little say in that. Despite the similarities of siblings, especially monozygotic (“identical”) twins, raised separately, we are still a product of culture and nurture. How we handle trauma is influenced by our genes, however it is the trauma itself that shapes us.
Values are not passed by DNA. We are more influenced by the lesson learned, the hardship overcome, and the love we receive. If it was just DNA, my role as Father would be so much easier.
The biggest influence on my view of DNA and family is via my closest first cousin growing up. She was six days older than me. She made me feel good about myself, helped me put my relationships with my sister into perspective, and especially made me eager to go visit our grandparents (where we got in so much trouble!). We did not stay in close touch as adults, but always enjoyed reuniting. Unbeknownst that I was a common connecting person, she became drinking buddies with my first wife (which explains part of why we divorced!). And years later when my cousin killed herself, I felt enormous guilt for not staying in closer touch, for not being someone she could turn to in her crisis. She was adopted. No DNA match. She was family. Period.
The grandfather we shared, Daddy Jim, was a step-grandfather. That lack of shared DNA also didn’t define the relationship. He was the grandfather I knew, and he cared for my grandmother in a way she needed up to the end of what was otherwise a life filled with many tragedies. That’s family, not DNA.
While there is a primal connection with those most genetically close, It isn’t DNA that gives meaning to our relationships. We even shun intimate partner relationships with close DNA matches (mostly in the west and recently! ).
DNA testing can be a dangerous or useful tool in a genealogist’s bag of tricks, even though it reveals very little about who we are.
Please contact me for further discussions…
References / Footnotes
- “Cousin Statistics,” ISOGG Wiki, November 8, 2020, https://isogg.org/wiki/Cousin_statistics.
- Amy Williams, “How Often Do Two Relatives Share DNA?,” HAPI-DNA (blog), November 3, 2020, https://hapi-dna.org/2020/11/how-often-do-two-relatives-share-dna-2/.
- Ashik Siddique, “DNA Ancestry Tests Are ‘Meaningless’ for Your Historical Genealogy Search,” Medical Daily, March 7, 2013, https://www.medicaldaily.com/dna-ancestry-tests-are-meaningless-your-historical-genealogy-search-244586.
- More reading with more considerations:
- “10 Pros and 10 Cons to Taking a DNA Test,” The Active Times, April 5, 2019, https://www.theactivetimes.com/healthy-living/dna-tests-pros-cons;
- “How DNA Testing Botched My Family’s Heritage, and Probably Yours, Too,” Gizmodo, accessed December 4, 2020, https://gizmodo.com/how-dna-testing-botched-my-familys-heritage-and-probab-1820932637;
- Cara Rose DeFabio, “If You’re Black, DNA Ancestry Results Can Reveal an Awkward Truth,” Splinter, accessed December 4, 2020, https://splinternews.com/if-you-re-black-dna-ancestry-results-can-reveal-an-awk-1793862284.
- There are sometimes unintended consequences in digging up the past. I generally agree with advice columnist Amy Dickinson on cases where DNA test disrupted families.
- “Ask Amy:: DNA Disclosure Disrupts Extended Family,” Toronto Sun, January 8, 2021, https://torontosun.com/life/relationships/ask-amy-dna-disclosure-disrupts-extended-family;
- “Ask Amy: DNA Match Creates a Moral Dilemma,” Providence Journal, Feb 12, 2020, https://www.providencejournal.com/entertainmentlife/20200212/ask-amy-dna-match-creates-moral-dilemma.
- “Ask Amy: DNA discoveries make (and break) families,” Chicago Tribune, Mar 22, 2021, https://www.chicagotribune.com/lifestyles/ask-amy/ct-aud-ask-amy-0322-20210322-ryncjde6vrbb5m5nwv3k3gaqsm-story.html
- “According to Rutgers anthropology professor Robin Fox, 80% of all marriages in history have been between second cousins or closer.”
See: “Your Family: Past, Present, and Future,” Wait But Why, January 28, 2014, https://waitbutwhy.com/2014/01/your-family-past-present-and-future.html
And: Richard Conniff, “Go Ahead, Kiss Your Cousin,” Discover Magazine, August 1, 2003, http://discovermagazine.com/2003/aug/featkiss.