In the US, cash must be accepted as payment for (edit: public) debt. However, there is no requirement that all transactions must accept all legal tender. A business owner can refuse to enter into a commercial relationship with you on the basis of your method of payment.

https://www.treasury.gov/resource-center/faqs/Currency/Pages...

It's legal but I believe it requires collecting payment upfront to make enforcement practical. The bus company example is pretty good - you get on the bus and pay how they prefer or you don't ride.

If you ate at a restaurant which had a 'no cash' policy, I'm not sure how you would resolve a situation with a client who was willing to pay in cash only. Would the restaurant be able to refuse your cash and say you ate without paying?

>If you ate at a restaurant which had a 'no cash' policy, I'm not sure how you would resolve a situation with a client who was willing to pay in cash only. Would the restaurant be able to refuse your cash and say you ate without paying?

I doubt it would be too difficult to find another customer who would swipe their own card in exchange for cash from the cash paying customer... free reward points after all. (Infact many people do something similar in India, we receive a fixed allowance which is tax exempt but can only be spent on food, this is given via a special debit card or vouchers. You pay for someone else's food using the voucher and take cash from them)

Legality seems to depend on the state, e.g. https://www.bostonglobe.com/business/2016/08/03/paying-cash-...

In general though, probably yes so long as it's stated in advance. And there are certainly many situations where you wouldn't expect to be able to use cash; I can't mail Amazon a stack of bills.

Yes it's legal.

Are online retailers in Poland required to take cash?

Land of the free. Home of the brave. It’s a “free” country.