Keep away from SIP welders as there complete turd. The wire feed never ever works right on them.I wasted alot of time when i was learning thinking i couldnt get the hang of it when it was down to the welder.
Ive never seen anyone get even half decent results with gasless.Id steer well clear.
Ive got a clarke 150 now and its great.Really easy to setup and use.Will do bodywork no problem or whack the power up and it`ll weld mounts,chassis ect no problem.
If your on machine marts emailing list get yourself to a vat free day and get one of the clarke ones.In my experiance there the best compromise between cost and quality for a starter.
Lincoln, Hobart or Miller make very good and reliable MIG welders with spares and service widely available. Buy one of their machines in the 180 or up amp ratting and you can not go wrong.
I have the same SIP machine in the corner. It was my first welder and I bought it before I had ever had a go at MIG welding. The SIP POS drove me to take up TIG welding thinking MIG was a poor process. One day I accidentally bought a Lincoln 185 MIG welder and my world changed, the TIG became a beer coaster. If you can afford a MIllermatic, buy one, I hear great things about it.
With what I know now, I could probably weld with a cheap welder, but when getting started a cheap welder is a false economy and will frustrate and ruin the learning curve.
Also, avoid cheap no-name wire and if it has sat for a year, don't try to weld with it. Rusty MIG wire is an aberration and will mess up the liner.
On flux cored welding: There are those that can make them work every bit as well as a gas-shielded machine. I have had it demonstrated and eaten crow on the subject matter. I am NOT one of the people who can make them work on automotive sheet metal, hence I can not endorse the process except for welding structural stuff around the farm or jobsite.