Put in your two pennyworth
Definition 1 of 1
Pro Tip 1/3Conversation Participation
The phrase encourages contributing to a conversation, even if not asked to. 
At the family dinner, Uncle Joe put in his two pennyworth about politics.
Pro Tip 2/3Casual Context
It's mostly used in casual or informal discussions rather than formal ones. 
When we were discussing holiday plans, everyone put in their two pennyworth.
Pro Tip 3/3Not Expertise-Driven
Use when opinions are personal and not necessarily based on expertise. 
She put in her two pennyworth about the new movie, even though she's not a film critic.