For starters, the Amazon marketplace is generally overpriced for second hand photo equpiment, at least in the UK. For example, they have EOS 3 bodies for £250 on right now. I bought mine for £67 on ebay and the usual closing price is £90-100. Camera shops like mifsuds will sell you one for £150, including a few months warranty.
Also, the depriciation of film equipment jumped when digital first showed up. Everyone started selling their film cameras. Prices dropped and dropped and dropped until pretty much everyone sold their film camera and got a digital one. The trade nowadays is mainly between film users which kind of stabilises the prices.
Also, as said, the top level cameras have kept their value while everything below them has tumbled to pennies. For example, F5 and EOS 1V bodies go for £250-500 depending on condition. The next one down, F100 and EOS 3 bodies go for £100. The next one down, F80/whatever and EOS 30 go for £50. The next one down goes for £30. So it is a bit of a game of diminishing returns. If someone is buying a film camera they'll most likely go for the top of the range. If you want to save some money go for the nex down. Anything below and it is not really worth!
If you really want another F5 have a look at camera shops instead of Amazon. There are a few F5 bodies in places like mifsuds or ffordes for less than £300. Grays in London has one for £285 with a year's (!!!) warranty.