>>9910532Super7's are fairly affordable. There's still some on Entertainment Earth and Amazon. As for the Japanese ones, they're all over the place in price, both on ebay and on Japanese websites. You can get one for anywhere between $5 and $60+ depending on what the seller put on them. There's no real consensus. The Keshi market is crazy like that, and there's not many communities to discuss Keshi collecting.
There's also lots of Keshi lines out there that you'll never have known existed.