NeoCash just went up for beta testing to Premium members. It looks like during the beta test, all items are half price - but they expire after only 3 months instead of the 12 months I had heard.
There is, however, some reassuring info in the FAQ:
NC Mall FAQ wrote:
Will Neocash items give my pets an advantage?
Definitely not. Neocash items are for those who wish to add a little something to their Neopets experience. Neocash items are used to affect how your Neopets appear on the website. They do not in any way effect the game play on the site.
At least they've THOUGHT about the economy and game balance. The only things you can buy at the moment are customisation items (mostly animated ones) and those weird expensive cakes that make your pet happy. No BD weapons, no books, no codestones. Although I still lament the man-hours spent drawing every one of these items for 52 species, hours I feel could be spent improving other aspects of Neopets hugely, I'm not as freaked out about NeoCash now as I was.
I'll never understand why TNT don't tell us openly about these things while they're still in the planning stage. Rumours rarely do TNT any favours.
Neopets Premium invites - PM or neomail me!
(Please?)