How do you enhance a bad listening room's accoustics without breaking the bank? thoughts?


I am looking at a cork wall covering product to help enhance my listening room acoustics. The room is in a condo and shares duty as an "L" shaped living / dinning room. As I have neighbor's on either side I was thinking of doing the one wall where the speakers are placed and the opposite wall where I have my sitting position (The Coach!).  I was thinking the entire sitting room wall (10x8) and the speaker area (10x8) on the opposite wall. This may also have the additional bonus of helping to reduce the noise coming from my stereo into those condo's next to me?
I was wondering what people's experience has been and successful materials used as wall coverings or panels.
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Pick up a dozen or two 5' artificial Ficus trees from a big box discount home dec store like At Home (@Home).  Scatter the artificial trees around the room focusing on behind and to the sides of the speakers and behind the listening position.  The artificial Ficus trees act as sound diffusers and absorbers.  

I bought mine at At Home for $40 each.  Completely converted my listening room, got rid of all kinds of room problems.  And they are appealing as room decorating accessories.  
All excellent and very much appreciated advise. I have much homework and reading to do! I love the pillow and chair idea, when the wife leaves the room, now that's thinking outside the box!
Thanks Bob.
https://www.thefoamfactory.com/acousticfoam/wedgefoam.html

For $123.00 you can get a box of 48 12 X 12 X 4" tiles. That is enough to do four 3 X 3' patches. It is cheap enough to allow you to experiment before you spend money on better looking treatment. There is nothing more effective and many people just keep the foam tile which looks very  technical. In a darkened theater environment it makes no difference anyway.