$10 for a BB is CHEAP...though from what I can see from the ad it looks OK. If your BB is feeling wrong after rebuild, make sure the bearing retainers are facing the correct way...an easy mistake to make but will NOT work right down there, and can do damage. Even if the old set is pitted, it should turn fairly smoothly not under load, but you may hear or feel a little chatter from the pitting. If I paid less then $10 for a BB, I would really doubt the quality,(the Suntour Superbe BB we just got for my son's bike go $65-$125 IF you can find em) but just for learning the process, Go for it...Good Luck, and Happy Wrenching. Welcome to the forum.