alright, i guess there are 3 main types of welders.
the first is an arc welder.
-possibly the simplest of all. simple to use, very few 'moving' parts etc and can be used just about anywhere. just very messy welds unless you are quite talented etc. hard to use on thinner steels. but can be used on very large thinkness steels.
next is a MIG welder. similar to TIG.
mig and tig stand for Magnesium and Tungsten Inert gas.
meaning, these welders you have a gas, magnesium or tungsten, both of which are.. Inert gasses. the gas is used to 'surround' the weld site and stop combustion/contamination of the weld by oxygen.
both welds when used with gas are very clean.
Mig welders can also be used without gas just like an arc welder.
id recommend a mig welder. however the prices may affect what you buy.
arc is cheapest at anywhere from 80-150.
mig comes in at around 400-800 for decent ones
Tig comes in at around 1200-2k.
this varies, these prices are from my local hardware shop in aus.
arc welders.
MIG/TIG welders