Jim posted:
You're late to the party...

The "legal" solution is you are out of luck; a private party can set any
payment method they want, including refusing cash of any denomination they
see fit.

See http://www.snopes.com/business/money/pennies.asp

A current example is Costco. Being a member, I pulled into their gas station
at Eugene, Or. and could not be served because I had only Visa, cash, or a
check to pay with. They accept ONLY MasterCard for gas, though they do accept
checks for in-store purchases.

Don