I don't know how thick those are, but I purchased my 1/2" magnets, 1/16" thick from this website: Buy Craft Magnets, Ceramic Magnets, & Pin Backs for Less
They're 48 for $4. I bought the 750 bulk for $30 and split them with someone else.
I ordered mine from ebay. i got 100 little round magnets for like $6.50. They stick well, perfect size, they are so cute! I don't even think I'll ever use that many I have like 95 left