Hey, so this room seems to have a lot of potential! While I understand that the white & wood combo might seem off, if you do little things like adding trim and cleaning up the corners it could actually work very well!
To start, could you please post some photos with a closer view of the edges of the wood siding and drywall boards; closet, door, and window frames; and the flooring situation (ie: what materials are there now). Also, beside your tv, is that a hole in the wall? And if so, what does it open up to??

Is the blue storage unit going to stay in your room? If so, choose bedding and curtains that also have some blue in them. Thrift stores are great places to buy bedding and decor items on a budget. You'll need curtain rods.

You have a nice big space to work with, and plenty of light. A good start. If you can't finish the flooring near the window, pull the blue rug a little away from the window to hide where the flooring ends. Use the brown rug beside it (near the open doorway) to hide the rest.

First things first. It appears you have 5-6 things plugged into one outlet including an window air conditioner. Hazardous situation. I suspect the wiring to this room is old and might not support modern electrical items. Do you ever trip breakers up there? Also how would you get out of this room in the event of a fire? I don't mean to overly frighten you, but this is serious situation. There are folding collapsible ladders that could hang over a windowsill so a person could get out. Look into that asap if you haven't already. Simplify all bedding and curtains and wall color to one or two off white colors. You can add some color back once you simplify things. I don't know where you enter this room but I think some rearranging could be big help. It is great you are trying to reinvent this space and do it on a shoestring budget. Just take care of safety issues first.

Given all the parameters of budget and such, here's a simple starting point in addition to addressing the safety issues noted by others.

I merely chose red and gray taking the clue from the bedding. It also happens to be a decent compliment to the flooring. It heed express the unifying aspect of some strategic color placement. All Paint for the budget, with the exception of a rug and window treatment.

I proposed painting a color accent across the back of the bed connecting the two door frames ( if that's not a true horizontal line, then pick the shorter door and strike the horizontal at that height.) Prime and paint the wood to match the walls to generate more cohesiveness. Remove the two rugs for one LARGE one that measures at least the width of the bed and two night stands. It should extend past the foot of the bed by at lest 4 to 5 feet if possible. Given that this size could be very expensive and hard to find, feel free to do this with two rugs. place the seam under the bed from head to foot so that it appears to be one rung at the sides of the bed.

Window treatment can be very simple and the space will come together if you hang simple curtains on a rod. place the rod at the ceiling, yo probably want them to stop short of the heater, but certainly full height. The rod can be a painted closet rod pole on economical wood brackets. All from the hardware store. Paint them all to match the wall.

I used a LARGE art piece as a headboard to suggest you find a way to create a head board. you can frame posters, a grid of photos, a series of guitars on hooks, etc. the objective is to create a large impact of a simple and cohesive item(s).

I also saw a fair amount of clues around the room related to projects in the making. this idea can completely work when those are finished if desired. I am guessing the closet is behind the bed? if not, I have a simple idea to create a closet at the paneling. Let me know if you want to see a sketch with that idea. It is important to start clearing the clutter to make the space feel more comfy and put together, so storage is a key element in your future.

Finally I see you're a gamer and probably sit on the floor. Find yourself a gaming chair, to if you have friend play too. they need not be expensive if you head to places like Walmart, Target, Costco, Sam's, etc. With the idea of gaming I wonder if you can have the TV on a surface as high as the desk, if so, I have an idea to suggest if you want to see the closet sketch.

And with all that, here's how a little paint and some simple drapes can revolutionize the room you call home.