Quoted from PinFever:speaker light kit 150
You are more than 2x off the mark on that guesstimate (unless it was bought from a scammer). It may look like it would cost as much as you said, but I don't charge anywhere near that price. $69 total for a GoT RGB speaker light kit and that acrylic design set.
Doug (SpeakerLightKits.com)
...,but more on topic. This looks like a clean game with a lot of nice add-ons at a great price. Good luck with the sale OP.