They're not open on Sundays anywhere. It's one of their founding principles to allow their employees to have Sunday off as a day of worship or family time. Nearly all of the music they play is Christian (usually instrumental hymns) and they have a great Christian merchandise selection throughout their store (so Christian themed stamps, Christmas has lots of nativities, not just Santa and snowmen, Easter has lots of crosses, not just bunnies and eggs, VBS kits, Noah's ark inspired stuff, Christian themed wall art, etc).
They normally have a coupon on the website that you can print out. You can use one a day. If you have a data enabled phone, you can also use your phone to show the coupon in the checkout line instead of having a paper copy.