Kind of funny story, I bought my two Garands at CMP and only got one clip per gun they should have been two per gun but I didn't complain. I asked about getting Clips for my Garand on another forum and someone corrected me by saying, "you mean magazines, don't you"
I came back and told him "No the Garand uses clips"
Anywho back to topic Most of the recommendations were for
http://www.ammogarand.com/clipsmagazines.html. I think there was another good place that was recommended, but I wound up going to a gun show and found a wooden box with 2 spam cans each had clips with ammo and cloth bandoleers, it turned out cheaper to buy at a gun show.