Limited edition collectibles are newly marketed items made in limited quantities. Sometimes they trade on the secondary market fairly quickly, and can even rise in value rapidly after they are issued. In the long run, however, they don’t generally demand the same high prices as time passes. Once initial demand has died down, the value often plummets.
Buy these pieces because you like them, but don’t count on them holding their value over time.
In the same vein, most new items made in mass quantities and marketed as collectibles will generally go down in value over time. This is especially true with fads. For example, remember Beanie Babies? While there are some exceptions, most of these cute little beanbags are worth far less now than what crazed collectors paid for them in the mid-1990s.
What makes an older collectible valuable is rarity, condition, and, of course, the demand for that particular item. The fact that toys, kitchen items and paper goods were mainly used and discarded in days gone by makes them harder to come by, and in many instances, worth more money as well.