Staples' current weekly ad (valid Jul 13 – Jul 19) features this gift card promotion on page 8:
Get a $20 Staples gift card via easy rebate when you buy $300 or more of MasterCard gift cards.
This is an added bonus if you're already currently purchasing MasterCard gift cards for manufactured spending 🙂
Terms and Conditions
Limit 1 rebate per household. Subject to availability. See gift cards for details, terms, conditions and (if applicable) fees. The MasterCard® gift card is issued by U.S. Bank National Association, pursuant to a license from MasterCard® International Incorporated. MasterCard® and the MasterCard® Brand Mark are registered trademarks of MasterCard® International Incorporated.