These things go in waves of feast or famine, we are in the feast phase atm. A certain item won't hit eBay for a while, then one or 2 will be listed and bidding will go nutty. People see this and want a piece of the action, so a flood of this product hits eBay and prices collapse for a long time.
A good example is the 1581 floppy drive. Several months back they were going for ~$250-$300. Now they are going for $50-$80.
