I'm on a tight budget. How decorate the walls of 14 year old bedroom?

Decorate or paint,not sure what your goal is

Can you post some pix of the existing room with furniture?

girl or boy?

There are usually large-size cans of paint at the 'big-box stores' that are unclaimed or for some reason not purchased (or returned?), - but are HEAVILY discounted in price. You could perhaps paint just one wall of the room.

Cover one wall with old records or the album cardboard covers that you can buy really cheap at a thrift store, Salvation Army, Goodwill etc. Or tape off a piece of a wall to do it as an accent. Then buy thin trim to put around it so it looks like its been framed.

If its a girl.... make a frame out of firring strips, stretch some chicken wire on the back of it and tack it down. Put some picture hanger hooks on the back. Now she can hang necklaces, bracelets and scarves through the wire randomly. Can use clothes pins to attach notes, photos, teen mags photos!

Older magazines are always a dime a dozen at garage sales, you an find some with pictures that you son or daughter might like and make a collage of them on one wall.

Definitely get the 14-yr-old involved in planning, budgeting, shopping & installation.

I’m a big fan of discounted paint, but the colors are rarely perfect.

So I buy the discounted sample sizes to modify the colors of the Light Base discounted gallon. Why Light Base? :

Light colors are easy to make darker.

Dark colors take 3x white paint to make them lighter.

Color Correction is based on the Color Wheel (see pic).

If the color is too saturated, then add some of the opposite color.

We look forward to a pic or two.