I got my wife's broken 4K monitor repaired for the grand cost of £3.50 a few weeks ago.
They were in the market for replacing it anyway because it's ten years old, but when it wouldn't turn on it that pushed their decision. Kinda pissed me off, because I was going to get it when the replacement arrived. So I figured it was already fucked, so it wouldn't hurt to see if it could be repaired.
My boss at work trained as an electrician in the Army, so we opened it, where he immediately clocked a capacitor that was slightly expanded. A multimeter reading confirmed it, so I ordered a replacement. 8p, but I had to buy a pack of five. Add the postage and it came to £3.50.
The repair took 10 minutes, and now I'm the proud owner of a 28" 4K AOC.