You know, the small things that can save you a lot of money. I’ll start:
You can get “hospital” powercables that are completely shielded for 20 bucks or so.
You can get anti vibration pucks for washing machines instead of spending 10 times that on the same product which is just labeled as “speaker pucks” instead.
Learning how to do diagnosis and repairs for common issues in amplifiers. Takes buying a few tools, multi meter, soldering iron, but you can save some serious cash on pieces labeled “as is” or “for parts” on FB marketplace, Craigslist, etc.