Prices and why?

I'm looking for two specific items, the Kilt and the Gladiator Armor. These two items I have only found with a lower price of around 40k while the upper of them goes for nearly 1 billion spina. Is it because they are old, hard to obtain items, are they just extremely popular with DPS looks and builds. Is it because people are overpricing them to pull up their market value or is it that they are not as expensive as they were

 

i dont understand build very well, the kilt just farmable anytime thats why they cheap while gladiator armor only obtainable during an event.

 

Price really depends on seller, along with other reasons, such as slots, xtals, dye, stat and refinement. ^_^