mig is definately the way to go for diy & quick repairs, shielding gas being the main issue with expense, most diy miggers go for the small halfords type bottles but they seem to dissapear quite alarmingly fast & aint cheap, better if you know a friendly landlord who can sort you with c02 from the beer pump ! or you can hire small bottles from boc etc
which last longer and you can offhire them if you only use occasionally for projects
i would avoid screwfix & other cheap welders alike as there ability to be set up nicely is crap,
you dont however have to fork out for a top notcher as there are plenty of good usable diy machines available such as sealey, clarke, sip etc
if you got a couple off hundred to spend on one then you can get some nice used pro machines like migatronic, murex, esab, lincoln to name a few
most newbies will struggle to set the machine up for the material there working on, a lot of this is down to poor equipment that doesnt function smoothly & wrong settings/choice of wire etc
small budget machines are very limited with power settings & adjustments meaning you have to end up compramising on your welding tecnique to get a result.
beware of second hand machines that have been abused/neglected as you will prob have to buy new torch, wire feed rolls etc all adds up!
i can offer advice to any diy-er whoes struggling to set there machine up, just gimme a call no prob
buy the biggest you can afford is my policy,160 amp is a good usefull size, i used to run 200 amps from my cooker socket!! back in the days,35 amp fuse