Mattress needed, mattress wanted

When I move in less than three weeks, I will need a twin-sized, comfortable mattress to go in my new room. It's been at least a year since I've slept on a twin-sized mattress. I would like this mattress to be CLEAN and CHEAP, but still comfortable. Any ideas on where I should look? I have issues sleeping on stranger's mattresses. I would also like it delivered to my new home, because I am well beyond chasing down mattresses and moving the beast of a mattress myself. (I've done too much of that in my college days.) Is this attainable? IKEA.com is great, but they don't deliver, do they?