The 18-55 lens is not on expensive one, in Hugary You can buy it for approx 25-35 EUR, and it is absolutely value for money.
(Ok, for beginners of course. At the moment I own 2 lens and a 5D body, and nothing else: 50 F1,4 and 85 F1,8 – and I will give money in the future only for lens with good quality. )
A used lens is of course always a lottery. By the 18-55 is not that case: You can be sure, that in a relative short time will break the aperture flat cable – the same pboblem like by th 17-85. You can find on the ebay cheap cable, but if You want to disassemble it, sometimes You just stare to that piece of plastic, which is impossible to screw out fom the other. I mean the front lens.
Front lens disassembling tool
I made for it a small tool, here are the pictures, You can make it too.
Desoldering of the flat cable
At first, You have to work quickly, not to damage the parts. Hot soldering iron, quick hands. You can use some extra tin on the tip of the tool to make a better heat-exchange with the parts.
At second, there is very recommended to protect the lens during this operation. I use for this (when I don’t forget it) some household aluminium foil. (A few weeks ago a small piece of hot tin was falling exactly on the shutterblade – which is of plastic…)
As I have only 2 hands, in the last days I tried to use a small wice (less then 10 EUR…)
The right screwdriver
The small screws which hold the contact plate are deep in their holes. Use an adecvate – thin – screwdriver. I have a cheep chinese one for this operation, and a strong one for normal use. (And on extra big one for stucked screws)
Here is a disassembling itinary – not checked by me yet (and in hungarian). Made by: Aquaworld.