You can buy a new TV with a Digital Tuner in it (look for the Freeview Tick symbol) or a Set Top Box (it does not necessarily need to go on top of the set) with a digital tuner in it.
There are other options for digital TV - a sky dish and Sky+ contract with a box costs about £8 per month and you can record and save 180 hours on the internal disk - watch one digital station and record another or record two programmes at the same time. My wife has set ours to record all Eastenders transmissions with just a couple of clicks.
Tesco Direct sell a Digital Receiver (set top box) for £15
Peccavi
April 2010