Record keeping systems for sales

Hey Folks,
I was wondering if anyone would be willing to share their system for recording sales. Right now I find our system is pretty clunky with many forms of records keeping that causes us to have data and information stored all over the place and we need to find a better system to do this. I will explain some of what we have now but I would love if anyone had found a good way to streamline:

Inventory and sales records

  • all our harvest records are done manually by the day on paper
  • for all our farmers market sales, we just record opening inventory and closing inventory, on paper and calculate how much is allocated to veg vs chicken at the end.
  • We also do online orders via our Square website that are handled separately.

Our challenge is that market is so busy and so cash dependent that we have been resistant to going to a full POS type system.

What do others do? how do you record sales and harvest inventory? I am open to any suggestions.