As jonno says, you can teach yourself the basics. Personally i would recommend having a few lessons with a local PGA pro, probably only cost you somewhere in the region of £10-15 per lesson but it will teach you the fundamentals of grip, posture and swing better than reading a book. Going to the range is a good idea also, but don't just go and buy 100 balls and try to thash them off in the shortest amount of time, ideally i would think 30-50 balls is ideal and each shot should start from scratch (i.e. dont just stand there with the same stance using an autoloader tee, you wouldn't do that on a golf course so why do that at the range).
If possible and you've got a field near you then just get some old balls (if you know someone who plays golf they usually have a few carrier bags full in the garage) and practice there, it cost's less and is just as good if not better as you'll be hitting off the grass.
With regards clubs, like jonno said, a good second hand set would be a good starting point. One of my mates has just started out and i've loaned him my old set whilst he gets going. A good starting set are Wilson Fat Shafts, nice deep cavity back irons that will help you get the ball in the air and be more forgiving than shallow back irons/blades, probably regular metal shafts. Steer clear of the woods as mentioned until you have got your sswing working well.
Other essentials are a pack of tees, golf shoes (you should be able to get a cheap pair fo £10-20 new), waterproofs (can get cheap ones also, no need for Galvin green!) due to our lovely summer weather and a golf bag.
