With our first child, we just grabbed any old crib mattress and went on our merry way. Turns out, she was a terrible horrible very bad sleeper. And while the mattress may not have had anything to do with her horrible sleep habits, we made sure that with our second, we researched better mattress and furniture choices -- not just because we wanted to get some shut-eye, but also due to the laundry list of chemicals and other products that are used in crib mattresses.
Truth be told, we're surrounded by chemicals every day, and while many parents are attempting to green up their nursery, budget is definitely a concern. But considering your baby sleeps (or *fingers crossed* will hopefully sleep) a minimum of 10-14 hours a day on the mattress, it might be best to forgo the fancy bedding and super duper changing table for something that could potentially affect their sleep patterns and their overall health.