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.
A bit of education allows you to spot obvious design mistakes or shortcomings in a given product. Speaker measurements help you understand what kind of value you are getting for the money.
There is huge variability in terms of value-for-money: certain brands overcharge for simple and traditional designs because they can, others put a lot of effort on R&D and it shows.