Up to £1000, expect the frame of the bike to be made of aluminium alloy. This hardtail mountain bike is lightweight and strong, and damage resistant.
At the lower end of the price point, expect a strong, sturdy bike that works well for lots of purposes.
The aluminium used at the higher price point bikes is of better quality, and the forming process used for these frames usually means that a more lightweight frame can be produced.
If you are lucky, you might spot a bargain – carbon framed bikes are very lightweight and strong, but they start at around £1300. If this is something you want, and you are prepared to buy a previous years model, you might get a great deal.