Dual Action Sander, bang for the buck

Got a lot of panel sanding in front of me. I need to pickup a 5-6" dual action sander. I'd like to get one that will work well, is easy to find pads for, easy to change pads, and the pads don't break the bank. What should I be looking at? Rather not spend $200+ but does a $50 work and last? Anything I spend takes away from the TIG welder bucket.