You could do them yourselves but wrapping fabric is no fun. I have GIK panels. I have 11 and cost about $1500 inc. freight. The most bang for the buck are the walls between you and the speakers known as first reflection point. If your system is in a dedicated room, it is easy.
How do you know what room treatments to use?
I am thinking improving my system with room treatment. My system sounds “loud” (distorted?) when turned up. It is a high resolution, very good $100K system built over several decades. I am getting a new preamp that will improve things but think that the room is significantly to blame. How can I actually tell what is amiss and what is needed?