The American Bible Society says there are 32 translations on the North American market, while Christian Book Distributors offers over 50. BibleGateway.com offers 23 English versions. In his research for a book on translations, Phoenix Seminary professor Paul Wegner identified nearly 100 English versions by 1950. He estimates there are twice as many now, although only a handful controls a dominant share of the market.
As I discuss in some detail here, we have so many translations for two reasons: (1) disagreement among scholars and theologians over which ancient documents should serve as the original "source texts" from which the English translation is then constructed, and (2) disagreements over how to best translate the selected source text into English. As a result of such disagreements, it seems that there's now at least one translation that will support most any theological position.
This makes traditional Protestant appeals to biblical authority suspect, and at least partially explains how and why we have so many different protestant sects today. Catholics at least vest authority in the Pope rather than in scripture, and since there's always a Pope alive to settle any theological misunderstandings, Catholics largely avoid (with a few notable exceptions) the schims that plague protestantism, though vesting such authority in any man has its own drawbacks.