CheckFreePay is the BillPay provider at Walmart at Kmart where you can pay your credit card bills for a small fee (can’t pay Amex cards). This is one option to unload gift cards if you don’t have any free avenues. I’ve used them occasionally in the past, especially Kmart, when I had a few $500 GCs left that didn’t make it worth the trip to Walmart.
BillPay can’t be done by cashiers. You have to go to Money Center at Walmart or Customer Service at Kmart.
Now addakorn on reddit is reporting that there’s a new limit put in place by CheckFreePay. As of 2/22/2016, there’s a $10k per month limit for credit card payments. The limit is most likely per credit card number, not per phone number (you give your phone number when making bill payments). The $10K limit will reset every calendar month.
If you see an error such as “declined, contact biller”, then most likely you’ve hit the limit.