Its just like you said diminishing stock.

I know people who REFUSE to pay that, hell a lot of people do. I know Ver 1's are pretty easy to find, but I've heard that theres alot of fakes for the ver 5. The two original v-pet versions I really want are the Ver 1 and Ver 5. Cause most of them were MIB condition with the comic and everthing. I do remember seeing those for cheap back when I didn't know anything about Japanese V-Pets. 2.0s and 3.0s were always more rare and expensive($40 was the lowest I ever saw a 2.0 for), but to see 1.0s as horribly inflated as they are now is probably the best example of eBay seller inflation. Then the stock this seller and another had ran out and prices started to climb drastically. Until about 2009, Pen X 1.0s were often on eBay for $9.99 from a very reputable seller. In 2007 I bought my first Digimon v-pet since my original back in 1997 a Pendulum X 1.5. What's really appalling is the prices of the Pendulum X series. There was another store that was selling Original V1s for $140+ back in 2007, but no one ever bought their products because MIB originals were selling for $30-50 commonly back then. I don't regret the purchase, as since then one in such pristine condition hasn't shown up(very few have shown up at all), but he started the trend that seems to've caught on on eBay. I actually ended up buying a near-mint 2.5 from him for about $85 because I was convinced they no longer existed. They were usually hard to come by versions(2.5, 4.5, 5.5, pen 0) and in moderate to mint condition, so a lot of people were forced to either go without or shell out. I forget his eBay name, but back in 2009 some lunatic started listing pendulums with their boxes and instructions and such for $90-200. Moreover, it's actually easy to spot the guy who started it. I'm really glad I have all of the older pets I want. Of course, I'd never sell my collection, but to see modern prices.

I have several limited edition v-pets that I bought for less than common versions go for now. If I were to sell it at current prices, I'd make as much as four times what I spent on many of them due to keeping the majority in like-mint condition, keeping the boxes, manuals, etc. I acquired the vast majority of my collection back in 2007-2008.

Digimon v pet box