Stack social has a deal which ends in 3 months where you get a $100 credit which can be used for any item StackSocial sells for $80.
This is how they describe themselves:
StackSocial scours the web for the newest software, gadgets & web services. Explore our giveaways, bundles, Pay What You Want deals & more.
They are reminiscent of Massdrop, LivingSocial and websites along those lines.
This is a credit to the account and not a gift card so its tied the the account which its purchased from.
You can't use additional discounts/coupon codes to buy the store credit BUT you can apply coupon codes to items that you pay for with this store credit.
Store Credit is active immediately after purchase.
Store credits never expire
They also have a Refer-A-Friend Program where you send a referral code to someone to signup for a StackSocial account. Once that new account makes a purchase it will get a $10 credit. The referrer will also get $10 credit.