Question

roaring economy
to buy goods on credit means to
promise to pay only a sale price promise to pay for goods later. pay only a discount price pay cash for goods.

Explanation:

When buying on credit, the key concept is deferred payment. It's not about a sale price (which is a temporary reduced price) or a discount price (a reduced price in general). Paying cash is the opposite of credit. Credit specifically means getting the goods now and promising to pay later.

Answer:

promise to pay for goods later.