For $200 take a look at Craigslist. IKEA also has some affordable options.
Ikea Alex Wall Shelf

If you are at all handy, you could make something for far less. This person claims to have done so for less than $20.
Desertdomicile DIY

For the dining area, I'm not sure the shelves work well on that wall as they don't have much space to breathe. Have you considered the wall adjacent to it?

Target and Michaels have art/frames/wall decor that you can mix and match using your color scheme and overall desired design. search Curated art/collections on their sites. Make the TV console as wide as the plugs or use a floor plant (with blue/green pot) to hide one of them. Add a couple of toss pillows to coordinate and a lamp.

Pull the sofa away from the right and back walls. No need for it to be jammed in the corner. Add a floor lamp.

Every room looks better with a tall plant. Live plant.

Maybe one of these original artworks would add some texture and contrast to your wall.

Here's some suggestion for your wall you might like......to know more about my Art work and collections please visit my shop -

http://www.pooviartgallery.com

While a gallery wall can look great, they're one of the hardest looks to pull off.

Create a backdrop for your TV. Wide enough to span the area to cover both plugs.

You might create this effect by installing a long matchstick blind behind the TV.