self hosted system for managing donations at museum

Hi folks, we're managing a museum where se don't issue tickets to avoid being taxed. But we can accept donations which are not taxable. I was wondering if there was sonlme self hosted tool out there that would help us record the donation and maybe even allow us to print a receipt for the visitor so that they can claim tax relief on the donation. If the tool could also help us track the sales of souvenirs, that would be a bonus.