Off course, there is some good reasons to use brazing or TIG instead of MIG (as I said in my 1st post: temperature control, clean process,...), but cost isn't the same at all. Even more when you need to practice (so consume, like, 1 full bottle ?).

I've spotted a MIG (Güde 155 and 172) that look correct (25-130A) for a rather cheap price (200-270€), if I can use it with pub or extingisher Co2, a 5kg coil of 0,6 or 0,8mm steel wire (30€), and have solid welds on ~1mm steel without transform it into a gruyère... I'd be pretty satisfied.
I would be tempted to give a try, but not before have some returns and be sure it can work.