It depends on the zoa. Eagle Eyes don't seem to grow quickly. Others like the pink/white palys I got from zoalover went from about 10 to well over 100 in a few months.
I always love walking into an LFS and seeing some awesome zoa. This particular LFS for me usually doesn't have any really nice looking zoa. Then I walked in and found this one in a frag section for $16 they look like your second ones:
These ones that Jim gave me (bonus frag even hehe) are still some of my favorites. There's a lot of interest locally in people wanting some of these: