Generally when I go to goodwill I'm never looking for anything in particular; just anything unusual, or a great deal or the perfect gift. Most of the goods are arranged neatly on shelves, which makes shopping easy. When it comes to the art, you have to be willing to dig through a pile of stacked frames, or a bin in the corner.
I always put in the effort to poke through the pile. Don't forget to use both hands, you may end up reorganizing the entire section by the time you're done. I've found some really great, and really really cheap pieces of art at goodwill. Don't forget those frames either - you can get a large decorative frame that you can replace the artwork in for very little money. My favorite piece is a small painting on a wood panel, it's of a harbor in Greece. It cost me $.99!
At the very least, you'll come across some truly terrible motel style watercolors and artist "originals" that will leave you laughing.
I've also found a lot of really awesome artwork at yard sales. I try to go yard sailing in the fancier neighborhoods (Falmouth Foreside, Yarmouth, Cumberland, Cape Elizabeth) because you'll find the best stuff. A friend of mine found a huge mirror in a heavy carved dark wood frame for $5 at a sale a few years back.
