I’ve been rummaging the web concerning acoustic design of peoples home studios. I’m Always surprised to see that people Think that bass traps from a specific brand is a must-have and that spending a couple of hundred dollars a piece is a good investment.
Why don’t you just make them yourself using Rockwool and breathing cloth in a wooden frame? Takes a couple of hours and you’ll get it in the correct dimensions for your specific room.
Cost? Nothing that will burden your wallet.