I bought one recently for my 34 year old daughter. I just got a lap blanket size because she wanted it more for relaxing in the evening on the couch as opposed to covering her bed.
When I did all my research I came to the conclusion that while they often recommend a blanket that weighs 10% of your body weight that that is often a bit much for newbies to weighted blankets so I got her a 10 pound one. I could not pay Bearaby prices but she wanted something that also looked good since it would be in her living area - I purchased this one that has a lot of good reviews:
https://www.amazon.com/gp/product/B09ZNTJNFH/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&th=1
There is an extra $20 coupon right now.