A590 with standard ROM and 2Meg Fast RAM, unboxed, sells (on ebay) for about €30-40.
GVP A530 is in great demand (dunno why) and sells for about €350 euro with or without box.
The best deal to look for as an A500 user is a GVP HD8+ Impact Series II. They are better than the A590 technically and aesthetically. 8-Meg RAM (instead of 2) and contoured to the shape of the Amiga. These sell for about €45 to €55 unboxed.
Of course the same items boxed, with all manuals and disks, in good condition can double the price for collectors.
I personally am looking for the illusive Power Computing / DCE Viper A530. However my chance of finding one (at a sensible price) is zero
