Possible slight conflict on interests, since they are my employer, but Agros do a pretty good range of bookcases for under £30. You can see one in the third of my pics. The shelves adjust enough to allow for five shelves of trade-sized books with a smaller shelf ideal for comics (or National Geographics in my case) plenty of colour options too. They come flatpacked and take about ten-fifteen minutes tops to put together. Delivery's pretty cheap as well if they dont fit in a car (£8.95).