If you are on a budget then finding great teen bedroom designs in your price range might be a bit discouraging. However, you can get a great bedroom for your teen without having to take out a second mortgage if you are willing to do a bit of legwork and put in some elbow grease.
The first thing you need to do is come to an agreement with your teen on how the room should look. Do they like specific colors or perhaps a theme of some sort? Once you have a broad idea of what you want, you need to find an inspiration for the room. This could be a particular item like a chair or a lamp that you could base the design of the room around, or you could scour magazines for a room that appeals to you and your teen and try to replicate that as close as you can.
Now that you have a general idea of what you want, you need to think about color, bedding, furniture and accessories.
The cheapest way to totally change the look of the room, and one that will go with most teen bedroom designs, is to simply paint it. Pick a color that goes with the design you have chosen and get out your brushes. If you want to add some pizazz you could do some faux painting or paint stripes or different colors on the walls. There are plenty of interesting paint techniques that can really make the room look neat and the best part is that you can learn to do most of them for free down at your local home improvement store