4Plus1 — Online discount coupons service

This WordPress-based marketing solution offers to get one coupon for free when buying 4 in a single purchase.

Customers can sign up using their Facebook accounts, search for ‘buy 4 get 1 free’ deals offered by local vendors, choose those they are interested in and pay for them. Ones the coupons are purchased, a notification is sent to the user with all the information necessary for redemption.

The vendor receives money only after the coupon is redeemed or its term has expired, which is implemented through integration with PayPal adaptive payments. The service owner, in his turn, gets percentage from the deal.