Not OP, but I was in the same boat as you. I loved having my bed on the floor but it did seem a little trashy. So I got this. Zinus has amazing bed frames that are easy to put together. I got a taller one for my guest bedroom as well.
Amazon sells some very low-to-the-ground platform bed frames that serve a similar purpose. We have this one, and it puts our mattress at about the same height as my son’s toddler bed: https://www.amazon.com/Zinus-Platforma-Mattress-Foundation-Boxspring/dp/B01LXM1FE6/ref=mp_s_a_1_3?crid=22QU7KSK3PDY8&keywords=low%2Bbed%2Bframe&qid=1557178239&s=gateway&sprefix=low%2Bbed%2B&sr=8-3&th=1&psc=1
I have a Zinus bedframe too, I initially didn't want a head bedboard after moving I made one myself out of foam board. Also, don't forget to check the Used/New link, sometimes I find 'Like New' stuff with great discounts
I'm also considering just buying this bed as a kind of intermediary until I can afford a sexier 1k+ piece. I'm just worried people might think it looks childish/cheap.
I got this bed frame from Amazon. Wanted something low profile and minimal since I don't like the look of tall beds.
https://allswellhome.com/products/the-allswell-hybrid-mattress
Went with a queen size. We use it on a steel frame with wood slats.
https://www.amazon.com/gp/product/B01LXM1FE6/
it replaced a low end mattress and box spring from a retail store that cost about the same amount ~10 years prior.
I think it is much better than that low end combo. It is about 3 years old now.
I’m unclear on what you are actually looking for recommendations on. A floor bed frame? A mattress? What size?
We have a twin floor bed in our daughters room for naps (she bed shares with me at night) from Srpout Kids and it is fantastic. Super easy to set up, would be super easy to store, and it flips over to grow with them. They also have a full size. Montessori Floor Bed
After a few months with our mattress on the floor, we got this bed frame because it’s only 6” off the ground: Zinus Platform Bed
And finally, I can’t recommend My Green Mattress highly enough. Made in the USA, organic, and no VOC’s or chemicals. They are fantastic.
We really like this one. Have two of them now.
Headboard is built by me, Frame is just a cheap Amazon one https://www.amazon.com/dp/B01LXM1FE6/ref=cm_sw_r_cp_api_i_r3jMDbGB8KA95