[put|throw] in {one's} two cents' worth

to share one's opinion on a topic that is under discussion

The politician put his two cents' worth into the debate, even though he wasn't a member of the panel.
The customer threw her two cents' worth at the cashier about the new store policy.
The armchair quarterback put his two cents' worth into the play call, even though he was sitting at home watching the game on TV.
The unsolicited advice from the stranger put my two cents' worth into perspective.
The know-it-all put their two cents' worth into every conversation, even when no one asked for it.