Money !

[Lindril Arvilya]

it states in fotr that frodo bought bill,fernys pony in bree for i believe 13 silver pennies.

So possibly, since silver pennies seem to be fairly high currency, perhaps they'd also use something like copper pennies, and gold coins would be worth a lot more.

They'd probably, in the most rural areas, use the barter system. i.e. I have a cow, Lord Dickie has chickens, so we don't "pay" for the milk/eggs, we just trade. It seems like a very "hobbity" sort of deal.