A few are going for much less than what they were worth new. I picked up one mon, with 2 eggs (3 for the price of 1) for 0.14 ETH, when they were selling for 0.971 ETH prior to being classed ''legendary'', so there are some bargains out there.
Once egg hatching comes into play, I expect we'll see a race to the bottom, then a steady appreciation in Gen 0s, as they become required for evolution in upcoming updates.
These are like digital pokemon cards! :D
Awesome, definitely working up some extra ETH soon and getting into it as I got a little but not enough.