Question to all the welders out there!!!
When someone asks a question like this, - it implies that they are not an experienced welder. That's OK. We all learn as we go.
But I think that if your first experiences welding are with flux core you will get very frustrated. It's difficult for an experienced welder to get good results with an inexpensive flux core welder. The extra amount of spatter means constant tip cleaning. They usually don't feed wire at as constant a speed as the better welders. That translates into more difficulty running a nice bead without blowing through sheet metal. Heat is your enemy when you're trying to avoid distortion. It will be harder to avoid when you find yourself fighting your welder. If a decent new mig is out of your price range, I'd consider buying used or farming the work out.
Keep in mind that it IS possible to do the work with flux core, but my advice is geared towards the guys with minimal experience.