Very expensive, probably from $35 to $60 sq. ft, the high end going towards installed which obviously you don't need. So lets say $30 at least.

Corian itself, which of course is just a name brand of solid surface material, can be very tough to find new unless you are a licensed contractor. I've had resellers slam the phone down on my ear when they find I don't meet their criteria, can be a batch of rude, snobby folks to deal with for some reason. Much easier to locate wilsonart/gibraltar, which is also a bit cheaper. If you are using it for lithos, only a limited selection of whites will do, not many others from what I have found will pass enough light.

Sometimes you can luck out on craigslist and find people practically giving it away, others seem to think it is made out of gold.