There are two big Neopets Item Database on the web. There is the Jellyneo Item Database and the Neododex Item Database. But since prices are usually user-submitted, they are hardly ever accurate.
Jellyneo is a great Item Database for buyable items, but with high-end items it’s terrible.
Same goes for the Neocodex Item Database, the price for higher end items is very off. Buyable items are easy to account for, as all that is required to account for those items is to setup a script to search the shop wizard to log the prices.