The following prices are a combination of my personal opinion and recent sales. Other members might give slightly different numbers but these should be fairly accurate.
Aquapolis
Kingdra $20
Lugia $30-40
Nidoking $28 (most recent ebay auction)
Skyridge
Celebi $30
Charizard $60-80+ (really hard to give a price on this one. Too few are sold)
Crobat $20-30
Golem $15
Ho Oh $25-30
Kabutops $15-20
Are those prices for the holo or reverse holo versions of them?
All the cards I listed only come in one version.
All the Skyridge cards that you mentioned also exist as Reverse Holo.
The Clefable Prerelease is said to have 3 ore 4 versions. (Different color for the Prerelease Stamp)
There is no evidence to suggest that the Prerelease Clefable has different coloured stamps. Until we find evidence then it's best to assume that only Green stamps exist.
There is no evidence to suggest that the Prerelease Clefable has different coloured stamps. Until we find evidence then it's best to assume that only Green stamps exist.
I found a really old post on the Gym that said Mike Boozer confirmed there were red (brown?) Prerelease Clefables, but none of those should have made it to the public because they were a production test to test differently-colored stamps. Unfortunately I can't find it again... stupid Google...