I always happen upon nifty gadgets that I end up keeping, and I always look for free things. So here's a thread for posting your free or inexpensive (hopefully under $15) gadgets - free preferred.
Cost: FREE! (hurray!)
I've been using this litle gadget for about 2 months now - I've put it in my Quick Launch bar, and it comes in real handy when testing site resolutions.
When you run it, it displays a list of open windows/applications. You simply select a window that you'd like to resize, and it'll show you the current size of the window. Just change that size to the desired size (like 800 pixels wide to test for 800x600), and press "Set" and it's changed.
It's small, free, and proven to be useful to me. I hope others find it useful, too.