One of the things about wine is the duty, which is fixed at around £2.50 a bottle, so if you by a bottle of wine for £3.50, you are really buying a £1 bottle of wine.
On the other hand, if you pay £10 for a bottle, you are getting a £7.50 bottle.
Price doesn't always reflect quality of course (or taste - which is personal), but it is something to bear in mind. Of course, it might also say something about the mark up applied to wine!