Samsung Pay has worked everywhere I tried it except at an IHOP. They have an unusual card reader built into their cash register and the card slot is very deep and we couldn't find any way to make it work. The cashier was very interested in getting it to work so we tried it several times moving the phone every way possible, but it just would not work. It has worked at many places where the card reader is built into the cash register, but this one was too deep. Otherwise, it has worked everywhere: Target, Walmart, Publix, Walgreens, Rite-Aid, K-Mart, Wendys, Taco Bell, Hardees, Auto Zone, Creative Graphics (a printing company in Lebanon, TN), US Post Office, etc. At first it did take me a few tries to figure out the best way to make the magnetic "sweet spot" do it's magic, but now it is no problem at almost all locations.
Now I just need an electronic drivers license and I won't have to carry my wallet at all.