Just wanted to share with you:
We've never had to pay full price for passes.
1.If you're taking the ferry P and O, check wether they're giving free adult tickets with each car.
2. Sky often have offers too.
3. Tesco vouchers: worth saving up
4. The French Disneyland Paris website often has an offer for a free pass if it's your birthday.
5. The French website FNAC great offers even during school holidays. Go to the "billeterie" section.
It's always worth investigating all of the above .