If you don't have the time or the inclination to research and figure it out yourself, I will just tell you the best and most economical way to approach DNA testing and genealogy.
First, identify one or more individuals in the oldest living generation in your family. This is your grandpa Joe, your great aunt Ethel, or your doting parents. Or, if you have reached the top of your family food chain, that is you. In short, any person who does not have both parents available for testing, should be tested.
If that lucky person is male:
Begin with a YDNA test from Family Tree DNA. The 37 marker test is sufficient, but if you have the funds, spring for the 67 marker test.
In addition, you should order and autosomal DNA test. If you are a member at AncestryDNA, start there. If not, you can start either at Family Tree DNA with their Family Finder test, or you can test with 23andMe.
Of course, ideally, you should eventually test at all three genetic genealogy testing companies.
If your oldest generation relative is female:
Begin with the autosomal DNA, in the same manner as listed above. Namely, if you are a member at AncestryDNA, start there. If not, you can start either at Family Tree DNA with their Family Finder test, or you can test with 23andMe.
Again, ideally, you should eventually test at all three genetic genealogy testing companies.
You will notice the absence of an mtDNA test recommendation, even though it is a test that can be used by both men and women. If you find yourself with a burning genealogical question on your direct maternal line, or if you have a habit of always crossing all "t's" and dotting all "i's" you can of course order mtDNA testing from Family Tree DNA. It isn't high on the priority list as the results aren't often genealogically applicable. But in all honesty, you never know what you are going to get until you get it, so there may be a hidden gem nestled in that mtDNA test just waiting for you to find it. If you are going to do it, you must order the Full Sequence mtDNA test from Family Tree DNA. It is the only respectable way to go.
Do you still have questions before you jump in? Just contact me and I will personally guide you through the testing process.