Clarke is about the best u can buy for the money, anything around 150 is ideal for genral purpose, think machine mart do a 160T for around 250 or something, argon/co2 75/25 or 80/20 is mostly recomended and best suited for steel work

Dont bother with gasless as there pretty shite tbh, the trouble with them is that the flux wire is hard (well almost impossible) to see the puddle and also they never really come in a high amp machines so u would be looking at welding 3mm max with any gasless