I've never seen them at walmart. There is a store down here called penney lane, and they sell them there. If you have a penney lane there, try looking in that store.
I don't think walmart... But i've been told numerous times that they have them in malls. Like, piercing stores there. I've been told they have them at spencers too,
Never seen them there, myself - I would think you'd get something like that where you get pro piercing supplies.