i have tried several "cheap" welders. Most of the 1-200 machines are ok with flux cored wire for 12guage and up to about 3/16, They just burn through anything thinner, and even on the thick stuff they are not as nice as a better machine.
I own a home depot lincoln. Its the most expensive one they sold the 3200 I think. It was around 500 and came with the gas regultor and some 0.023 solid wire(no tank)
I also work with a few professional miller and lincoln machines.
The 3200 is a great machine for the price and automotive work. Its actually identical to the lincoln 175 or something. Basically the one that sells for around 800 at most welding shops. First the 3200 series works on 110. No special AC hookup. Really nice voltage regulator and phase control. The arc is constant even with an extension cord and other equipment running or poor metal quality. Thats what you are paying for besides the brand name.
As for its ability when I first started it burned through everthing thinner than 12 guage, and it splattered the rest. I ran out and bought a tank of 75 /25 to use the thinner 0.023 wire. Still burned a little but much less and much cleaner
With a little practice here's what I have learned.
Flux cored 0.035 works great for everything automotive. 16 guage-1/4 are no problem. You have to be carefull on the thinner stuff, and adjust your feed rate and your hand speed, but the machine works well. With flux cored you will need to have a wire brush handy to clean the slagg. A drill and wire wheel work real well. The weld quality itself is very good under the slagg.
As for gas or flux cored. Flux cored is cheaper to use. My tank was 120 plus about 35 to fill. If you use gas you have to keep filling it back up. Fyi don't buy a little tank you will be out of gas in 20 min. Spend the extra mony and buy a decent sized tank. As for penetration. gas or flux have little difference.
Its the wire diamater and welding current that matter. What lincoln is describing in there manual is the 0.023 wire is thinner and requires gas to shield it. Since its thinner it will not hold as much current before melting so less burning through and less penatration on thick metal.
0.035 flux cored wire is thicker. So it can handle more current and make a deeper weld. If you use a similar diamater wire with gas you will get equal weld depth and penetration. If you go with bigger wire, and more current, even deeper weld.
btw when talking about arc welding Gas is for shielding the arc. It does not burn or make the metal hot.
Electricity does all the work of making heat.
Finally get an auto darkening helmet. either a cheap one from ebay or a good one from a welding shop. So much nicer to see where you are going to start the arc than trying to fight the flip lids. Personally a cheap one is fine as long as you have a shade control knob. 9,10,12,13 different lens adjustment is nice if you switch from low current to high alot.
Or for a cheap starter welder, with a great return policy,,go to wally world 
