"Food stamps" now are actually a debit card called an "EBT" card, at least in my state (not sure if the food stamp program is state-by-state or national), which is nice and discreet.
Discreet-ish. At least in my state the cashier had to pull out a book and make sure the constraints weren't violated. It's a slow process and when there's a line you can feel all the eyes on you.