I use two different cast iron skillets. I use an 8" when I'm doing ribs at 225-250, but when I'm smoking chicken breasts or burgers I smoke them at about 325-350, and only for 1 hour for chicken or 30 minutes for burgers, I've found that my wood chunks will flare up with the 8" skillet so I bought a 15" skillet and put the chunks at the outer edges where it doesn't get as hot. Oh... and I also found that the 15" skillet wouldn't keep my chunks smoking at 225 to 250.
For cheap skillets, if you can't find anything in a thrift store, or don't want the hassle of checking every one in town, my skillets were really cheap at Big Lots if you have those in your area.