Putting dimes in the dollar jar 

Making a small or worthless contribution (see also putting pennies in the pound jar for British)

She might as well be putting dimes in the dollar jar with the amount of help she's contributing.

Putting dimes in the dollar jar by Ellgrace June 23, 2020

Two dimes on the belly of a biscuit 

A mildly valuable item discovered in the bowels or auxilliary to something of comparably lower value.

"I found a timex watch in the trunk of that wrecked Kia."

"Aw damn .... two dimes on the belly of a biscuit!"

Two dimes on the belly of a biscuit by Lil' Ree-Ree June 20, 2017