Here is a thought: grocers should display the fully burdened price they pay for goods, then show a 1.5 percent mark-up. The burden would include everything: electric, water, space lease, government compliance overhead, labor, &c. Oh, and the burdened price would include what the supplier charged, including shipping, handling, and anything else that gets tacked on.
Heels-up thinks the retail store is the problem. Full transparency would show who is doing the gouging.