I used to cashier all day, and my feet ached. I never did find a good shoe (but I never tried any of the really expensive ones, because, well, I earned a cashier’s wage). I found that some relatively cheap shoes (like the Dr. Scholl’s ones) did okay as long as they were replaced frequently. My coworkers also recommended Skechers, or Birkenstocks if you can afford them.
It makes a difference if you stand all the time or if you are allowed to walk around. Walking is at least something the feet were meant to do, while standing in one place isn’t – and this distinction should inform the choice of shoes.
The only thing that really helped my feet medium-term was getting inserts from a foot doctor. I had orthopedic inserts made from a cast of the shape of my feet, and cortizone shots to my heels, and that helped for a while, but the only thing that helped long-term was quitting that job. I wish I had quit sooner, before the damage was so permanent. Even though I quit five years ago, I still have occasional pain, especially when I’ve been off my feet for a long period (sleeping, or at my desk job) and stand up to go somewhere. It still hurts like that for a few minutes until everything gets stretched out.
I know it’s not really very practical advice, to stop damaging yourself when you probably need your job. It’s a trade-off, though: what you need now, to how much future pain you are willing to risk.