hey, I'm a skydiver myself, depending on what you want depends on the cost.
a tandem skydive expect to pay roughly ÂŁ200, thats from 15,000 ft and about a minute of freefall time, i recommend this if you want to try it out, if you like it then do a static line or aff course.
a static line course varies, at our uni its ÂŁ165 for 3 jumps but i think that is a deal we have with a dropzone. a static line course involves jumping from about 3,000 ft with an automatic deploying system so no need to worry about pulling your chute. I would only recommend this if you have a low amount of money and just want to jump from a plane as it only involves 3 seconds of freefall time.
If you want to become a qualified skydiver you could do Aff. it well set you back about ÂŁ1500 or ÂŁ300ish a level. that involves jumping from 15,000 ft with about a minute of freefall. you jump with 2 instructors for your first 3 levels and one from there after. you also pull your own chute.
Both static line and Aff require a days ground training before you can jump. tandem is about 20 mins training.