If you go to Home Depot, you can get corian sample blocks (2" by 2" by a little over 1/4") for free ...
If you go to Lowes, you have to pay for the sample blocks, but they're cheap ... like 50 cents each?
If you know some hard surface countertop installers in your area, they may have cutoffs and scrap laying about that they would be more than happy to sell or give away... They also make for great cutting boards and potrests, for the homeowners who installed that particular style, so most of those companies go ahead and fabricate some out of the leftovers to give as extras to their customers or to sell.