Overall prices for used Emulators have weakened recently as the new Ultras and ESI2000 arrive on the secondhand market, and impact E4 and earlier model prices. Recent models vary on price mainly due to specification.
Older models vary on price according to condition, quality of the sample library and any extras.
Some EIII's have come on the market recently at low prices. These are highly complex musical computers with a large number of components, some of which are very hard to replace or repair. Repair bills can be expensive, and can make the difference between scrap and value. The vintage analog synthesizer market has seen a major revival over the last 10 years, with anything with analog filters being collectable. However the same has not happened to vintage samplers, because a cheap modern sampler is 10 times more powerful, much easier to use and sounds far better.