alright i took some of the classes here in florida and it is true with a 300 dollar 110 mig you can not get deep penetration on thicker metals but there is a loopole if you cannot spend the money on a $500+ a good cheap trick with a small welder is to get a torch. the problem with the low powered migs is they dont properly heat the metal to penetrate.. what you can do is buy heat markers and a propane or acetelyne torch will heat the metal to a point where the low powered mig will penetrate deep enuff for a quality weld.

oh yeah your gonna have to spend at least another 150 on a argon argon/co2 tan.. flux core will blow through thinner metals.