Although the phrase is now somewhat outdated, in British English we sometimes say "I'd like to add my tupp'orth to the debate" - meaning "I'd like to add a few thoughts of my own..." The phrase literally means (colloquially) "my tuppenny worth", i.e. "my two pennies' worth".
What would be the nearest equivalent in US English? (It doesn't necessarily have to be a phrase involving coinage - I'm just looking for a widely-used idiom.)