Download o2 moments on your smart phone, and search for odeon and get a free odeon priority card they are normally worth £2 ish.
When you redeem online ,
Also if you already have it you can get a extra 500 point by entering the code
Each time you buy popcorn or cinema tickets etc you can accumulate points to spend on free tickets or popcorn etc.
Also u don't need to be a o2 customer, just know someone who is on o2..
Launch app enter their number and the they will send a text to the number.
Enter the special code received and done