Yes, I have one and so do each of my kids. I was very sceptical, but when I use it I fall asleep really quickly. They do seem to help.
We used to have a very heavy comforter that we tried to use on cold winter nights but eventually went back to normal weight blankets. You might try sleeping with heavy layers of bedding before buying a gravity blanket. Some people like them but they can feel restrictive. I found that I would enjoy the extra warmth initially but then about half way through the night feel like I couldn't move comfortably.
My wife has one on her side of the bed and she loves it. I sometimes will snuggle up under it with her... My 5 yr old twins like to lay under it too until they decide to move and then they have us move it off them since they are fairly much " stuck " under it.....
Got an 18-pounder on sale online at Walmart. More comfortable than I expected. It does have weight (glass beads) but isn't as hot as I feared. Not sure yet that it helped me sleep any better than I would have otherwise. I need to give it time.
I think big lots has them for about half that though. I was just in marshalls a couple of days ago and saw the 30ish ones was why I mentioned them but a while back I did see them in big lots and like I said I think theirs was 15 or 20... You can find some good deals though with a little research.
I was thinking of one (for insomnia and/or chronic pain symptoms) but after reading up and talking to others I don't think there'd be any benefit for me. I move around a lot during my sleep, and when I wake up throughout the night trying to get back to sleep I shift positions a lot, so I think it would be more of a bother. It's my understanding that there's a formula for what weight you would buy. YMMV
I think there is a formula to it, but I don't know it but my wife has a 15 lb and absolutely loves it on her half of the bed.