After our trip to Cedar point, I was annoyed that I had paid $10 for a refillable drink cup thinking I saved $5 by buying the cup online only to find out that at the park they were on sale for $6. At the time, I was really annoyed but didn't think about it again for a couple days.
I sent a quick email to the email address on the Cedar Point website with my order number and basically just said what happened. I didn't ask for a refund, instead I just figured that I would see what they did. I received a call yesterday from someone from Cedar Point. They apologized and are sending me a check for $4.
Works for me!