We have a lot of money-related idioms in English. Here are 10 really cool ones.
Penny for your thoughts
If your friend is quiet and thinking to him or herself, you might say “penny for your thoughts” to get them to talk to you.
My two cents
If you want to give someone some simple advice without putting any pressure on them, you can say that you just want to give them your “two cents.” I've seen this abbreviated as M2C online.
Put your money where your mouth is
If someone is all talk, but no action, you might ask them to put their money where their mouth is. You might say this to your friend who is always bragging about how good he is at a certain videogame if you wanted to challenge him.
Dime a dozen
If something is really cheap or commonplace, you might say it's a dime a dozen. For example, having a YouTube channel used to be really unique, but you might say that nowadays Youtubers are a dime a dozen.
Turn on a dime
This expression used to refer to quickly changing course in a small boat, but nowadays is used when someone changes their opinion or strategy completely. For example, if your boss was going to offer you a promotion but decided to fire you instead, we might say she turned on a dime.
As phony as a three-dollar bill
That Rolex your friend has might be as phony as a $3 bill!
Red cent
If you don't have any money at all, you might say that you don't even have a red cent.
Dollar for dollar
That apartment you rented might be more expensive, but it's bigger. Each square meter cost less. Dollar-for-dollar, it was a better deal.
Dollars for doughnuts
If you're really sure about something, you could say that you'll bet dollars to doughnuts that it's true. This means that you would be willing to risk 100 dollars to get 100 doughnuts, because you are so sure you would win.
A pretty penny
If something costs a lot of money, it costs a pretty penny. For example, many sports cars cost a pretty penny.
I hope you found the list useful. Let me know if you have any questions!