When we got the mattress, it came in a box and took a week or so to reach full expansion.  It had a mild foam odor that also dissipated before we put it in service.  [We let it sit in an unused bedroom for a few weeks while we waited for the trailer to arrive.]  One nice thing about the mattress was that it was very economical.  I checked the price on Amazon and it's gone up quite a bit, but is still less costly than many other comparable mattresses.  I tried to put a link to Amazon in the post, but the Mr. Google doesn't seem to want to cooperate, so here is the mattress description:  

Ultimately, you will need to find one that will meet your needs. My choice may not be what you need.