I'm not sure how much shipping you've done but I was selling full time on eBay and I never paid over $100 to ship anything accept an old full size slot machine that I repaired and had to ship to San Francisco. Even at 250+ lbs and was packed in a crate I made out of 2x4s and thin plywood that measured 8 feet around and 42" tall. The buyer set up the transport with a semi truck. When I tried to find out costs to ship I saw prices that were all over the place. It comes down to who has a truck in your area and has a load going neae your destination (shipping wars perfect example). Figure they spent $400 for the machine, I doubt they paid more for shipping than the value of it or they would have bought one that was closer for more money. They checked cost before they bought it and the machine they bought was not picked for a collection or any reason other than the condition and it was a 4 real machine that was in a lowboy case which is a very small cabinet for an old electromechanical. The buyer was a wife for her husband, so there were a few limitations placed on the purchase, size and cost were probably the main factors.
What I'm saying is a 70 lb feild telescope that was just under the largest size that USPS carried was under $100 to ship, so $200 for a receiver (even going from Miami to Seattle) is simply gouging a buyer. Weight, box size and zone set prices, extra insurance is only a few extra dollars, but I doubt that they would accept that value without an investigation.
You do realize that people run scams on these types of sales on ebay. Fake buyer (known by seller) buys it then the seller sends a box with a different item and buyer then claims it arrived damaged, seller files an insurance claim to pay the buyer back. Buyer owns the same receiver that's broken just in case they ask to see it. Nobody knows what was actually sent but can't prove it wasn't the receiver that the buyer took in for inspection. I always suspect anything with big prices to be a scam in action. I was making insurance claims based on buyers telling me things arrived damaged but they were not required to show proof of damage according to eBay rules. I paid to get some items shipped back to me after they got their refund and found them to work fine even one that has an obvious hammer smash spot on the front corner of the item, but they reused the original shipping box to return it and the box had no damage to it at all! eBay did nothing when I reported this and the buyer took 2 weeks before they reported it as damaged! The funny thing was that it still worked fine even though they reported it as not functioning properly!