If we want to promote healthier choices, the food stamps can be color coded. Green for veggies, red for meat, etc. The receipt could easily show how much in each kind of scrip was required. No scrip for snack food, and none for soda.
If I were running the program there would be a separate register and a separate line for food stamps at every participating store above a certain size. Hopefully the line would be longer and move more slowly than others. Maximum inconvenience and embarrassment for food stamp shoppers, speed up the lines for everyone else.
And, just to be sure we taxpayers get out money's worth, demand a discount from grocery stores on redeeming scrip.
Great ideas!