Cheap. Dirt Cheap. And somewhat Dirty Cheap things. When I head over to the old Dig N Save on Park St., that's what I'm looking for. I tend to go there when I've got crafting or cosplaying ideas, but don't want to spend much money on them. Like Goodwill is being too expensive fancy, so I need really cheap Dig N Save goodies.
Get a whole bunch of picture frames of varying sizes, doesn't matter the color, just that they still have the glass and a wooden frame. Take out the glass and paint all the frames a fun color or a several coordinating fun colors. Return the glass, add some pics, and you have a high end looking wall display. Frames are only 25-50 cents apiece here. That's such a bargain. I got a 2-pack of Ikea frames still in the packaging.
Have a sewing project where you need random smaller bits of fabric? Go through the clothes bins and look for shirts/pants you can cut up for their fabric. I'm going to make a patchwork little bag (think the carry-all bag Hermione has in Deathly Hallows), and was able to get plenty of fabric for less than $2. Clothes are $1 per pound here.
Glass vases for sharing flowers with your neighbors can be had for $0.50-1 and then you can tell them to keep the vase.
If you are a cosplayer with a good imagination, this place is a treasure trove of resources on the cheap.
If I were handy enough with the power sander I'd check out the wood furniture in the back more closely. The prices are cheaper than at the other St. Vinny's sites and Goodwill. You will literally have to dig through the bins of clothes though. No fancy hangers for things here. Just wear some clothes you don't mind getting dusty and get digging.