Use an accounting program like Quicken or Quickbooks, and you will not have to have a filing system. Record everything properly at time of expenditure, then just keep receipts grouped by months. Never need to look at them again unless you get into a tax audit, so do keep them.
That's what I do. I have an accordian file. I used hanging file folders, but small papers will fall out. At the end of each year, all receipts for each month get a paper clip, and stuck in a large envelope with all the rest of that years paperwork.
Do not meddle in the affairs of dragons. Because you are crunchy and taste like chicken.
Endless Summer Lawn Care