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.
Take the time to get your listening environment maximized (positioning of speakers, rugs, furniture, etc.). Once you have done this a good quality dsp (minidsp) for a 2, 2.1, etc. channel system can work wonders.
Invest your money in the best possible recordings ahead of new equipment.