We bought a race car bed off the internet (can't remember the website). DH had always wanted one when he was a kid. Its close to the ground and has sides, but fits a single bed mattress. We bought a thick foam mattress, as if you bought an innerspring mattress it'd be very heavy to make. DS loves it but doesn't stop him from coming into our bed during the night. Also, its difficult to get out of if you fall asleep in it with DS when you're pregnant .