Listen guys - dont waste money in those places - you'll just get sore wrists (lol).
Go to
www.preloved.com and put in a search on adult movies. Loads of people are selling dvd's for a few quid each or less. Start with one or two to check quality and save tons. You can easily get ripped for £25 a movie unless you really want some specialised stuff in the shops.
Disclaimer: I have never watched a porno ever coz they are rude but know loads of people that do and save tons.