cash box spreadsheet

Hi
Hope I can explain myself good enough. I'm making a spreadsheet that will be used for balancing sales:

I'm starting each day with a cash box of 3000 in different coins and bills. In the end of the day I want to save 3000 to put back in the cash box for the next day and the rest of the money I put on a bank account.

However I want to save as much of the small value coins and bills and bank the larger bills. At first I thought that this would be quite simple to do however I soon got cought in a complex if-else-or web. I also found that there was a limit to how many if-statements I could use in a row which means that I couldn't compensate for every single situation.

I would be very grateful if someone had an idea how I can simplify the functions or if someone has a better idea how to construct this spreadsheet.

Thank you