You can use GiftFolio.com as a reward for employees, rewards for good behavior, or thank you gifts. The recipient won't know the cash value and they can even send a thank you automatically when they redeem. This is great for companies that use their corporate cards to expense recognition awards or rewards for employees directly. Best of all, you have end-to-end tracking.
Links:
[1] http://www.giftfolio.com/
[2] http://www.incentivelogic.com/giftfolio-redemption-center
[3] http://www.incentivelogic.com/direct-rewards