[HPsquared]

I suppose he could barter for it.

If person A holds on to the borrowed cash and doesn't spend it, that money doesn't circulate (the velocity of money decreases).

If person A doesn't take the loan, there is less money in the system (money supply is reduced).

If there's less money circulating, people won't "bid-up" the prices of food and gas as much, reducing their price (assuming constant supply of food and gas).