ALL sizes are in stock and the price does not change whether you pick up a twin, or a gigantic Cal King. And you've heard us say it here before, pick up a Cal King, cut it in half and share it with your dorm mate and save! Shipping is a flat $1.00 no matter how many you buy and there's no tax except in UT. SERTA REJUVENATOR 4 INCH MATTRESS TOPPER DEAL