try any 2nd hand funiture shop.
Better yet. Buy one from IKEA. Take out the screws. Return it back for a refund. Complain about the hassle it was to return the good back. They will then give you a little more money. And then have a freind pick up the desk (minus the screws) at the reject counter at next to nix.
Freind of mine works IKEA in the returns department, and some of the stories amaze me.