I was given an iphone.
It had a broken screen and was very battered.
I replaced the screen ( £6 Ebay) and it worked fine. ( Replacing the screen is easy and fun; instructions are all over the internet. )
The trouble is that thecharging socket does not engage unless it is held in with all my might, or strapped in with two zip ties ( which makes it impossible to use while charging).
This is my ten minute repair using what I had to hand . . . and it works.
Step 1: Tools.
Saw, drill and scissors.