weldings easy but it depends how much your doing to warrent buying the kit, id suggest a MIG set, if it involves bodywork, stay well clear of gasless, i use 0.6mm wire for everything and use proper gas, with a good set like mine, proper gas and thin mire i can lay a continious line of weld on a body panel without 'blowing' through.
but like i say it depends what your welding, ive also got a DC Tig set and i hardly ever use the mig now as the tig is far better at everything i do, i only use the mig now if ive got to just stick 2 bigish pieces of metal together for something
to sum up, get a MIG, spend all you can afford to at least £300 and get a proper mig mix gas in a big bottle.