I once "fixed" a old mac laptop (the white shell one from like mid 2000's) by putting a penny under the heatsink for the gpu. I didn't have a re-flow setup or a oven I was willing to bake the board in to fix it but it worked for years like that.
I also got really lucky with a monitor I bought for dirt cheap because the backlight didn't work (I had been repairing backlight issues with monitors for a while and re-selling them to fund my other projects) I took the back panel off to find that all of the cables for the backlight were disconnected. Fastest easiest fix ever. Since it was a very expensive monitor (usually) I decided to keep it. I think I used it for a good 10 years before I gave it away. I would never have spent the $$$ to buy one new like it but I think I spent $50+shipping for what was basically a $700 monitor, brand new.