We decorated my daughters bedroom over the summer, she is 15 and growing up fast, she hated the flowery wallpaper and wanted something a bit different. Although her wardrobe was technically sound, it is old, boring knotty pine from Ikea, so we agreed to paint it rather than buy new.
This is before (sorry stock picture as we forgot to take one in our enthusiasm)
We painted it matt black (paint £10) and then pasted strips of The Financial Times onto the panels. The FT has an attractive pink tinge to it. It also has fewer coloured pictures and more text which I think is better for decorating with. If you wanted you could strip the paper roughly and do a patchwork type design. FT costs £2.50. To seal any paper project like this use clear varnish. This will stop it from looking tatty and becoming marked.
Here's how it looks now
and then a small set of table top drawers from Ikea
(not mine but this is how they looked before - you get the idea)
I changed the knobs. These were around £2.99 from Homebargains (for 4)
Keep your eyes peeled for funky wrapping paper (make sure its of thicker quality), or rolls of wallpaper (charity shops and carboot sales will sell left over rolls cheap). Old books which are falling to bits can be rescued for decoupage craft. Also scraps of fabric can be used to jazz up furniture and boxes. I reuse every scrap.