all up to the buyer/seller in the end i suppose. if someone wants it that bad they'll pay for it. problem is with ebay sellers set high prices based on historical sale prices, but with rare items there is always someone who is willing to throw down for it! so the behavior of a few desperate people end up dictating the current market value
besides the rfx another example is proteus RAM cards. on ebay some people are selling these 20year old 256kb pcmcia cards for more than $100 (more than the original retail price!) there was a guy locally who was selling one and said 'ebay prices are xx for this rare item' and i had to work to make him realize that the retail price was $99 in 1991 and that ebay pricing is not indicative of actual value in the least (but value is subjective so... oh well!). its the same with the PCD-50 or 60 scsi card readers. they were going for ~$70 until they ran out and now you can only find them on ebay installed into old enclosures for $250+!! what?
anyway, i got my e4xt ultra (including both esynth roms & 16MB flash ram) for $400 and found a 8 out expansion at random music store in Belgium for $100. I probably spent another $100 +/- on the icydock and a 160bg pata hd.. i'm not sure what I would pay for a sampler that has the same specs as mine but anything pushing $600 seems like too much.
there
is a lot of hype surrounding emu modules.. vintage keys units go for as much or more than the 32MB rom card's of the same name. in the end most of these products are just repackaged versions of the same thing though. as jah mentioned to me at some point they really have been milking the proteus 1/2/3 soundset for ever (which is basically the EIII sample library)- like it was their entire business model! the differences between an emulator 4 and an e4xt ultra are fairly miniscule.. so with that in mind, there are people who sell e4x turbos or e6400s on ebay for ~200 or LESS which is a great deal. does the exact same thing as the ultra (minus a few not too useful features.. anybody actually use beatmunger regularly? the FIR and aural exciter are the only useful processing tools in the sample menu imo) and memory upgrades are cheap as hell. to see the variation in prices from ~200-1500 for basically the same machine speaks to the fact that there is no objective criteria determining the selling prices of these machines. the RFX/platinum is the most extreme example of this