Do something meaningful with 20 yuan (don't be superficial)

Hello, landlord, this is my little idea:

First, change 20 yuan into 200 coins with face value 1 min!

Then four people each take 50 yuan, go to 200 classrooms respectively, and post a proposal or a note behind the door, which reads: Diligence and thrift, starting from 1! Put another coin on it!

I can only think of this because of my limited ability ... and I think leaving your names on the proposal is the best commemoration and proof.