The sport of mountain biking has seen some amazing advances in technology with bikes now incorporating automotive technology such as carbon fibre frames, full suspension and damping with hydraulic disc brakes. The sky really is the limit and so the advice is to get some advice…
Before buying it may be worth hiring or borrowing a bike to see how you like it.
Apart from your bike, you also need to get some decent clothing and of course a helmet is an absolute must.
Like most other sports now, the need for proper hydration has been recognized so make sure you have either a bottle or other drinks system if you are going on a long ride.