
Originally Posted by
Dibs
Causalien, I think there are several factors that play into whether very rare items will increase or decrease in value. I can give you some examples.
I used to play Runescape when I was in high school. For the first holiday event that they had, they released a special set of coloured party hats. These hats were subsequently never made available again, leaving a fixed number of party hats circulating in the game world. These hats were also purely cosmetic; they did not boost your character's abilities in any way. In that sense it was purely a status indicator. The colour of the hat also made a difference - the pink ones were worth the most.
Naturally, as more players started playing the game, and as more gold entered the economy, the value of these hats skyrocketed. During a second christmas event they released Santa Hats, also with a limited acquirement period. These hats also became very expensive, but were around 10-50x cheaper than party hats.
My friend recently sold his set of party hats this year for around $2300, and invested the proceeds into stocks.
I still play Team Fortress 2, which is developed by Valve. I am sure you are aware that this game has cosmetic hats for sale. In particular, the extremely rare ones with special cosmetic effects will go for over 300$. TF2 also has a similar "party-hat" items. The first few hats that were linked to promotions for other games were limited in availability, creating a fixed amount available for the community. Someone who paid ~40$ for a game a few years ago received a set of bunny ears that are worth over $80 at the moment. If you installed TF2 on a mac during a small promotional time window, you got a pair of in game earbuds that are worth over 30$ today. The prices of these particular items has constantly increased over time. These items are typically used as a de facto currency in high value trades.
However, I don't know if these examples are similar to your situation. It seems that you can acquire rare items but there is no limited supply for sale. You can follow simple supply/demand logic to see how the price might change. More of these rare items coming into the market will force a downward pressure on the price. Expansion and newer items with better capabilities will obviously send the prices down. The only thing that will keep prices up is if there is and increasing demand for the item. This can come from more new players wanting to buy items. It could also come if the item achieves some cosmetic value. However cosmetic value tends to depend highly on the availability of the item, and if it is widely available it will not be widely sought after.