If you find yourself a little far off from the city center and can only see an abandoned gas station, then you might be in luck. Gas stations and pharmacies have registers that often have small coins such as quarters.
If your grocery store cashier or fast food attendant doesn’t want to exchange quarters or doesn’t have enough for a $1 bill, consider making a small purchase.
I doubt you will have much luck finding an arcade in the United States these days, but if you happen to be in a pinch – say stuck with your wife at the mall and in desperate need of some quarters – you can stop by the old arcade.