Wish I had seen this a week ago - make a $300 purchase on there, full fiat price sadly.
Quick question, can more than one code be applied to a single purchase at a time?
Yes you can use more than 1 gift card code if these are authentic gift cards and not coupons (99.99% the OP is selling gift cards so take the answer as YES).
The only downside here is that if you get $500 of gift codes and he sends you 100 x $5 codes, you have to manually enter 100 codes into the site to complete the purchase. That could be annoying.