Sony is hosting a Spend $100, Get $15 back event starting on Tuesday, February 21.
This sadly ends after the current flash sale.
Credit for info below.
From Tuesday, February 21 at 12:01am PT/3:01am ET until Tuesday, February 28 at 11:59pm PT, anyone in the United States, Canada, or Mexico who spends $100 through the PlayStation Store will receive a $15 credit back on or before March 14.
If you spend $100 between February 21 and February 28, the $15 credit code will be sent to you via system notification on PlayStation 4 or PlayStation Vita, XMB message on PS3, or email on or before March 14. The code must be redeemed by 11:59pm PT on March 31. No matter how much money you spend during the promotion period, only one $15 credit can be earned.
Here’s some of the details of the promotion:
Promotion is available to legal U.S., Canada, and Mexico residents with an account for use of the PlayStation Network (an "Account") registered in their country of residency who are 18 or older and who have spent $100.00 or more using the PSN Wallet between February 21st, 2017 12:01AM PT and February 28th, 2017 11:59PM PT. Third party application purchases not made through the PSN wallet are excluded. Each Account may only accrue a total of $15 in PSN Wallet credits pursuant to this promotion.
The promotion code ("Code") is good for one qualifying Account to redeem the PSN Wallet credit via the PlayStation Store. Code expires at 11:59PM PT on March 31th, 2017 and must be redeemed prior to this time. Code cannot be returned or exchanged for cash, may not be used for any other purpose and will not be replaced if lost, stolen, or damaged. You will receive the redemption Code on or before March 14th, 2017 via XMB message on PS3, system notification on PS4, PS Vita, or the email account used to set up your Account Sign-in ID.