A business is not required to accept cash as payment for product or services, however, there is almost always a however,,,.
Let's say you purchase a new truck,. tractor, airplane, mink coat, what have you. For the sake of illustration the cost of
the item is $75 K (cheap plane) They agree to accept $50K as down payment. You cut a check for $50 K for the down payment
and sign a note for the remainder. The remainder is a legal debt for value received by you and can as such be paid by cash.
Cash is legal tender for all debt , public and private. The caveat here is I do not at the moment have a Uniform Security Agreement
in front of me to determine if there is a clause therein to define method of payment.