Due to covid making so many working from home, wanting to spiff up their online look with a key, the portable pop up type of screens have gone way up in price and down in availability. You can buy big rectangular cloth screens on ebay and amazon, I did, but most of these are not fully opaque, requiring them to be doubled-over if there’s any kind of light behind the cloth, or the addition of a black cloth behind them. i ended up hanging black cloth behind my green, but I knew it was not the best and was picking it based on size/dollar. It works for my uses. Photographers paper rolls remain a reasonable option, Savage is one such company but there are others. If you can get matte vinyl instead of paper, I think that’s more durable, but will cost more. I have never heard a bad word about Rose Brand in New York, and they will send you, (on request) an actual sample card of their green and blue screen materials for evaluation. Rose brand serves TV and Stage pros.
The other thing I always suggest for home studio greenscreen is cheap kitchen vinyl sheet flooring; the cheapest, marked-down, end-roll stuff they sell, as long as the reverse side has a nontextured, coated base. These take chromakey or limbo cove paints well, (after a primer coat of Killz brand latex primer) and are much more durable than paper, if heavier. They curve great. It’s a little too heavy to be really very portable, though it can be rolled up and stored more compactly in the studio.
I am a DIY video artist/experimental filmmaker who only works for myself on my own projects. So I waited for a working pro to respond before I did. I shoot everything from animations and models of space ships to people walking on the moon in my 10 x 12 living room. I hang backdrops from a “clothesline” circling my ceiling but if your subject is stationary, a C stand will do. The most keyable backdrops I use are felt (several different colors) and plastic outdoor tarps (white is my color of choice for the tarps). Both are opaque and easy to store and use.