Room Treatment, Panel Sound Diffusers


So I am setting up a third sound system in a spare bedroom.  I want to really get the walls and perhaps ceiling treated for optimal sound.  The bed will be taken out.  I will put in high quality duplexes like the ones sold by Cullen Cables.  However, there are a bunch of different sound diffuser panels with many being quite expensive.  I am going to do the install myself so nothing too complicated.  Looking for advice on the type of wall treatment that works but won't break the bank.

Thanks!
jaymark
What is your sources?

I have acoustic panels from,

https://www.gikacoustics.com/

in a small bedroom with a floor stander. Look at my virtual system. If not for the fact that 2 of my sources are analog, SACD, tuner, I would not get the panels from these guys. The panels do the job but in an all-digital setup that is not how I would do it.

I am playing some ZZ Top via a digital stream right now at 75 db. Sounds fabulous in this small room. 
Just FYI, OP, treating a room is not done well 1 panel at a time.

You need to get a critical mass before you hear much benefits.  2 Panels for instance are unlikely to do much alone.
Post removed 
Well there are a lot of questions to be answered.  How big is the room, what kind of speakers (monitors or floor standers for example).  It will most likely need some corner bass traps.  Listen to it without a lot of acoustic treatment before you go forward.  I have used acoustimac with mostly excellent resutls.