Back in 2014 I needed a really cheap bed really quick so I ordered this bed and mattress topper from Amazon Prime.
https://www.amazon.com/gp/product/B005A4OP8Y/ref=oh_aui_detailpage_o09_s01?ie=UTF8&psc=1
https://www.amazon.com/gp/product/B004AR5X92/ref=oh_aui_detailpage_o07_s00?ie=UTF8&psc=1
It is one of the most comfortable beds I have ever slept on. I now have it in one of my guest rooms and most of my family and friends prefer to sleep in the room with that bed! So I would highly recommend those products.