When C. and T. were sharing a room (and M. was still in with G & I), I found a great "bed in a bag" Harry Potter set on clearance. This was something that would work for both kids, so I bought two for their bunk beds.
We painted the walls blue to match (the carpet was already blue) and I made curtains and a wall hanging from fabric found at Wal-fart.
But T's over that--and into Star Wars in a BIG way! We re-did the girls' room completely after G and I moved upstairs, but there wasn't really a need (or a budget) to re-do T's room. But as G. was cleaning out his closet, he found a lot of Star Wars toys and posters, and as I was cleaning out the linen closet, I found some Star Wars pillow cases that we'd bought when C. was little.
I went to Wal-fart and found some fabric to make curtains (4 yards x $4/yard) and a fleece panel ($5) and solid black sheet ($3). Here's everything put together:
I sewed the fleece panel onto the twin sheet, and then cut down an old black and white comforter and wrapped the sheet around the edges and sewed it down.
I took some of the leftover curtain fabric and sewed it onto an old solid black toss pillow.
It's so cool how this poster matches the pillow cases:
The only thing is that I don't think I like the blue walls with this stuff, and the blue walls got stained from the leaky roof and we have no more paint to touch up, so..... what color would you paint the walls?