How many members are in the 'Crazy 88' from "Kill Bill"?

that would be 88 :)

Kill Bill may not have been meant to be in two parts originally, but it works out fairly well. Thurman's final battle against Lui and her associates has a higher body count, more dismemberment and unrelenting action than most Hollywood action films in their entirety. This is definitely the showpiece of the first half and its great to see veteran kung fu star Gordon Liu front and center through much of it. Liu plays the masked leader of the Crazy 88's, a band of 88 fighters working for O-Ren.

(kungfucinema, no longer online)

In Kill Bill Vol. 2, when Bill is speaking to Budd, he talks about the Bride decimating the Crazy 88, and says something like, "of course, there weren't really 88 of them." From memory. I always thought it was less that 88.

Wikia agrees that there were in fact less than 88.
http://killbill.wikia.com/wiki/Crazy_88

Numerous sources are saying that there are 40 credited actors to the Crazy 88 and that "Jonathan R. From Bouncing Ferret Films" did a frame-by-frame analysis and found 82 total. (However, every source that references this Jonathan R is secondary, and no primary source appears to exist -- so take that for what it is.)
http://www.moviemistakes.com/member2418/title3650/answers