Betas, Diamond Items, and RaresThere are three types of items most sought-after in AJ - betas, rares, and diamond items.
A beta is an item that was only available during the beta-testing stage of Animal Jam. Just because something isn't in stores anymore does NOT mean it is beta. Something is only considered "beta" if it was ONLY available during Animal Jam's beta-testing stage. Examples of beta items include: Arctic Hood, RC Car, and Flytrap.
Now, with the arctic hood, not all of them are beta. An arctic hood is a colored hood with a fur rim and a pointed end, and when you put it on, it gives your character eyelashes. However, beta arctic hoods have green eyelashes, and non-beta arctic hoods have black eyelashes. Of course, the beta version is worth much more, because betas are always worth a lot. By "a lot," I don't mean just a couple Rare Item Mondays. Some betas are actually worth a lot of other betas combined.
A diamond item is an item that is (or was) only purchased in the Diamond Shop. Diamonds are the rarer currency in Animal Jam, so if a certain diamond item costs 5 diamonds, it is possibly worth a rare. When you're looking at a diamond item displayed in a shop or on a trade list, it always has an emblem of a diamond in the corner of it.
Lastly, we have rares. Rares can be won in adventures or as a Rare Item Monday - every Monday, there's a rare item available in stores, but it's only available for that day. Some rares are worth more than others. RIMs are worth the least.
As with betas and diamond items, you can win rares in adventures. When you look at a rare displayed in a shop or on a trade list, it has a golden rectangle in the corner that says "rare."