We are going to purchase a Full bed for our guest room, and will move it into DS's room in 12-18 months when he switches from a toddler bed to a big kid bed (and then at some point our guest room will become a nursery for hypothetical baby #2).

What kind of mattress should I get? Is memory foam ok for kids? Should I get something inexpensive for now while it's a guest bed/little kid bed, then upgrade when he is bigger and heavier?

On this thread: http://boards.hellobee.com/topic/do-you-have-one-of-those-fancy-mattresses#post-586302
I saw a reco for a mattress on Amazon that's a great price, but it's memory foam... thoughts?