I have a half-bathroom with just a toilet and sink. The sink is old and just hangs from the wall with the pipes showing. The sink is on one wall and the toilet is on the other. It's 6ft. long, 3ft. wide. I want to decorate and change it's sterile look but I'm on a fix budget. Do you have any suggestion on how I can improve this small box bathroom? Any help is welcomed.Thank you.

There are several things you can do to fix up this powder room.

If the sink and toilet is in good shape. You can simply install new plumbing to it that is not rusty or old looking. They make custom traps and pipes that are quite nice now and clean up all the ugly exposed pipes. Changing the fixture on the sink will also do a lot to improve things.
Use some bright colors with accents. Nice throw rug on floor if its tiled. New light fixture. Perhaps a new border on the top of wall. Add a chair rail and trims. All can do a lot to improve this look without spending a lot of cash.

An inexpensive update can be achieved by attaching a piece of cloth hanging from the pedestal sink, even if it is only attached by sticky-backed velcro. That, combined with matching or contrasting window and shower curtains, and maybe a small floor rug, can add a splash of color and brighten up the whole space, for just a few dollars.

Oops, I just reread the original post. I don't guess you'll be needing the shower curtain.