FTDNA has a good deal going. 39.00 Y-DNA test.
A 12-marker test is smaller, obviously, than a 37 marker or 67 marker test: the more they test, the more they’ve got to compare to other people and the more surely they can say you’re related.
If you’re female, this doesn’t help you—but! if you’ve got a paternal-side male reachable, if you pay for the test and they’ll do the simple cheek swab and mail it in, you’ll have access to the results, password and all. A birth-father, father’s brother-of-the-same-father, or son or grandson of same will have the same Y chromosome.
If you want to get in on the ground floor of DNA, this is a reliable company, a pioneer in the field of genetic testing for genealogy. They will not give you modern relationships or medical info unless you pay for a very much ‘tighter’ and differently targeted test and indicate it’s for that purpose. They also will accept GEDCOM (universal genealogical tree access) info and notify you of other matches in their DB: that is the only sense in which it will tell you about a relationship—usually 8th-degree cousins, of which you have potentially, very, very, very many. There is also the possibility of upgrading the test later: read their information. This is a really deeply discounted quality test.