Start with a 6 bottle kit. Youngs actually do a kit which includes the bottles, but any used screw cap wine bottles will do and cost nothing. Don't just buy a can of concentrate, but a full kit which includes all the neccessary components. This will set you back about £7.50. A 1 gallon glass jar, (a demijohn) is also required, complete with fermentation trap and bored rubber bung which fit the jar. You'll have the rest from beermaking. In my opinion, white wine kits tend to give better results if you are in a hurry. £16 should cover it, which is about what you'd pay for 6 bottles of cheap wine. Thereafter the 6 bottle kits work out about £1.25 per bottle.
There are economies of scale. A 30 bottle kit takes the same time and effort, worlks out about 85p a bottle and lasts almost twice as long!