Just noticed you mentioned potty litter
Those potty litters from a pet store are not safe.The safest you'd manage would be Yesterday's News cat litter or a high quality Chinchilla sand(which you would not find)and the cat litter would certainly not be the best option.It's very big for hamsters,especially dwarf hamsters,and could deter them from using the litter tray.
The reason for the potty litter from pet stores being unsafe is they're made from unsafe minerals,clay,etc.These things are not safe for hamsters or any other pet for that matter.
Sterilized play sand ends up considerably cheaper than high quality Chinchilla sand(which would need online ordering and would cost far more for a tiny fraction of product let alone shipping and importation costs).I know Kaytee make a bath sand but it costs twice or more of what you'd pay for play sand and is near impossible to find,making it not worth putting in so much effort and way more money than necessary into getting.