Giftcardmall are selling $50 Toys R Us gift cards for $40. Resale value is ~80% so with 0.5% portal for Ebay + Ebay bucks you'll come out slightly ahead. Limit is 2 so not very scalable.
Edit: Here's the link: http://www.ebay.com/itm/261487435841
Edit: Here's the link: http://www.ebay.com/itm/261487435841