Like already said, make sure you know its a dwarf!

HERE is a site that tells how to determine if the frog you're really buying is a ADF or an ACF. I've often seen some people mislabel them in petstores, so be careful. =]

I have an African clawed frog, and she's around 3-4". She is so much fun, and loves to take food from my fingers. Its so cute how they eat^^.

Good luck!