If buying a used mattress is out of the question, then buying a "green" mattress is probably the next best option. But even that can be tricky. You want to steer clear of all the greenwashing (and there's a lot of it in mattress world).
The Green Guide's Mattress Buying Guide is a great place to start, if you're on the hunt for a new green mattress.
It's a useful resource on a tricky topic.
image via Soapstar D'lux; Flickr.com