I bought the
Belkin Clear Grip Vue for $29 USD. (Found it cheapest on
eBay -some places it's as high as $49.) I believe there are three color choices - I went with clear.
Then I also bought some cheap TPU cases on
eBay. (Same material as the Belkin.) They work okay, but you can definitely tell the difference in quality. The Belkin case is thicker, tougher and grip-ier, and the material is more likely to hold its form. The cheap cases look okay but the material is pretty thin and likely to stretch out of shape, especially along the bottom, where there is just a thin strip of plastic around the USB port.
If you search on
eBay for silicon cases similar to the Belkin, do a search for "iPad TPU case."
I bought a few cheap TPU cases in case I wanted to switch things up but now that I have them all in hand, it's more likely I'll just leave the Belkin on.