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.
You can avoid expensive potentiometers or stepped attenuators by using digital attenuation.
You can avoid an expensive preamp using your DAC instead, provided you do not have analog sources.
You can avoid an expensive CD transport by converting your CDs to FLAC and using off-the-shelf hardware as a digital player running open source software.
You can avoid heavy power supplies and huge heatsinks by buying a class D power amplifier.