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 pennies in the pound jar

Making a very small or worthless contribution (see also: putting dimes in the dollar jar for American)

She might as well be putting pennies in the pound jar with the help she's contributing.