So, you are just selling the discs only without the case? Your listing isn't very clear, and your picture shows the cover art, so if that is not included, you may just want to have a pic of just the discs. If the listing is just for the discs without the case, it's not worth it for me to pay $5 to ship 2 discs that should only cost $2 to ship. But, you already have a bidder, so looks like it's going to sell regardless. Thanks and good luck!
USPS 1st Class Mail is a fixed rate to anywhere in the U.S. from anywhere in the U.S., and it maxes out at around $3.50 for a 13oz package. Media Mail is even less than that. The only way it costs $5 or more is if you're shipping it via Priority Mail, which you did not indicate from what I could see.
I'm not trying to give you a hard time or tell you how to run your business, but I like to know what I'm getting before I bid on something, and full disclosure on what the customer is getting and shipping methods helps to alleviate a lot of unnecessary questions. I ship items all around the world for a living and just thought I'd provide some additional insight on the costs in case you may have been unaware of some of these options. Again, good luck with your listing.