I’ve slept on a sleeper chair before. If you go onto Amazon and type in “sleeper chair” you’ll get a bunch of chairs that convert Into twin beds. I only slept on it for two nights. My friend had it for guests in her apartment when I visited. I dont know which exact one it was, but she got it on Amazon. As a chair, it was great. As a bed it did the job. She asked for honest input and I told her that if she had a guest staying longer than two nights she would need to get a foam mattress topper to soften it. It was very hard, but we partied a bit both nights so I fell asleep quickly (aka, stumbled into chair-bed and passed out). 😁 Of course, the whole reason behind a chair bed is that you don’t have a lot of space, so storing a foam mattress topper would probably be a problem, but maybe they roll up really small. I don’t know. I doubt all this was very helpful, but I got to relive a fun weekend with an old friend by typing it all up, so I’m happy! More on reddit.com

I have a twin-size daybed from IKEA that has a frame on 3 sides. With throw pillows on, it works as a couch for company but is a comfortable bed too. More on reddit.com

Honestly - a Murphy bed setup is much more comfortable if you can get past the old Muppet movie tenement scene jokes. More on reddit.com

Recommend going to Jordan's. So many options in your price range and they're quality is great. Just an example (they have even smaller at Twin size mattress or you could get up to queen mattress): https://www.jordans.com/product/living-room/living-room-seating/sofa-beds/j-furniture-chesapeake-full-sleeper-loveseat-with-memory-foam-mattress-lz2410201?srsltid=AfmBOorqnxbQQTwb4BaOnKUWbsBUTL2wWDCnhhZLVokCMGjT6ZUAoiTI More on reddit.com