Harbor Freight has a dual mig welder that does flux wire or gas sheilded. To do gas you need a bottle, regulator, tank, special handle/hose and tips(and probably a cart to keep everything close to eachother). I think the $119 version is flux only.
The Dual Purpose welders often come with just the handle/hose and internal set up to use gas but not the regulator or bottle. Some kits include the regulator and some extra tips too.
I looked at both and decided to go with a dual purpose welder and ended up with a Lincoln MigPak 15 which I think is a canadian name for the SP175- It is a 220 volt welder that puts out 30-175 amps of welding power. It came with the regulator, hoses, handle, tips, face sheild, etc... and I paid about $400 on ebay for it. The bottle was about $200 with a fill. Then I bought a cart at HF for $40 (I think). Also a self darkening helmet for $50. Solid wire and flux wire cost about the same and can be bought all over the place- HF, home depo, sears, lowes, etc...
A friend of mine has the flux welder you are looking at and gets by with it. He spends more time cleaning up the welds than I do, but grinding wheels and flapper discs are cheaper that a big welder. The problem he runs into is getting thin enough flux wire to weld the body panels. If the wire is too thick and you have the amps set too high you can burn holes rather than welding.
There are two or three things to think about with welders- Input, output and duty cycle.
Input- 110 or 220, if 220 single phase or dual?
Output- how many amps? (higher amps for thicker metal). 90amps might get you by for 3/8ths steel. I wouldn't use it for frame welds, but it'll do exhuast pipes, metal fence posts, fabbed brackets and body panels (see above).
Duty cycle- For home use not that important. Duty cycle means basically many of the next ten minutes can I use it before it has to rest- 10% one minute 50%=five minutes. This isn't too critical for hobby welding or with mig welders. Hobby welders doing body panels need to sticth weld= 1" of weld, space 1" weld... during the 'space' the welder is resting. Also, most mig welders have thermal protection circuits that will shut down the welder if it gets to hot, the way it does when it exceeds the duty cycle. If you are doing industrial welding duty cycle is more critical.
