Back in the good 'ol days I used to be broke and did several things to save money. Sometimes I was just being petty.
If I had a car battery that was weak and wouldn’t take a charge I would dissolve epsom salt in distilled water and add it to the cells, it broke up sulfation and often I would get another 6 months to 3 years out of a “junk” battery. Now if a cell was damaged or collapsed it wont work, however conditioning batteries like this can give a “4 year” battery a life span of 8-10 years.
I had my brake shoes relined by a local guy I was able to barter with.
It wasn’t uncommon for me to put used brake pads on my cars, sometimes I would go to the junkyard and find the best ones off of different vehicles, it was cheap. One time I had brake pads and rotors from 4 different vehicles on my car.
One time I had a dodge van with bad brake lines to the rear, I just plugged off the rear line at the proportioning valve. Worked good until one of the front lines blew out, then I hit a tree.
I used to buy some of my gas at a junkyard, They would pump out tanks when the cars got in, they would sell the gas cheap, it was all mixed together so any bad fuel was diluted enough it rarely caused trouble.
Non automotive things___
When I take a shower when its cold out I plug the tub and let the heat from the water dissipate into the house before I drain the tub. Why would I dump water I paid to heat down the drain. I want the most heat for my money.
I used to drink powdered milk, and made my OJ from concentrate.
Anyone care to add to the list.