Here are some idioms with the word say
1. What you say is a hard blow to me. ( = your opinion).
2. How much do you want for an old car? Let’s say $10000 ( sugest).
3. What do you say to a coffee? ( come and have coffee).
4. They say there will be some cut for next salary. ( there is a vague report).
5. Jane goes without saying. ( no need to tell anything).
6. I say, have you read the report? ( have no meaning, the I say is an exclamation to attract attention).
7. Well Niko has said his say. ( given opinion).
8. I would tell my Robert that I want to resign this month but when I met him, I had no say in the matter. ( no power to speak).
9. There is an old saying” No one is perfect”. (a wise word).