Linenspa 8 Inch Memory Foam and Innerspring Hybrid-Mattress - Medium-Firm Feel - Full https://www.amazon.com/dp/B01IU6RN9G/ref=cm_sw_r_cp_api_i_qqbzFbXBDP67A

I’ve been sleeping on this one for months with my daughter who is now almost 2. It is on the floor of her room and quite comfortable. She’s rolled off it before and not even woken up. Though usually I’m on the outside and there’s a wall on her side. When she gets a little bigger, I’ll buy a low frame for it and it will just be her big girl bed at that point.