Some of your items are about right like accelerators but your Video Toaster Hardware items are close to twice as much as they should be. There is lots of them on the market so they dont sell at high prices. TBCs for example dont sell for more than $100 even the Kitchen sync equipped with the S-Video card will only sell for about $100.
The Amiga is a tough one to gauge as they sell a different prices depending on time of year and location.
The biggest drawback is that your selling them on Amazon. Ebay is unfortunately the only good place to sell Amiga items. You just simply wont get the traffic through Amazon. And to make matters worse Amazon only allows US buyers so your limiting your audience.