Why Items' Prices Increase and Decrease Strangely in PoE

Economy is a big issue in PoE which determines whether you are able to buy good PoE items and gears as many as you want, thus influencing your performance. Prices of items are one of cores in economy. However, the changeable prices often make players confused. Many people can't understand the change of prices. For example, when you are in week 3 of the league, the prices of low-end items have already dropped to where they should be, but good gear keeps getting more expensive every day. You bought Kaom's  for 360c, some days later it's starting at 420c. So many people ask how the prices works in PoE. The reasons we summarize are as follows:

First, some items are popular in certain period. Flavor of the month items always get more expensive. Righteous fire is really popular now (it seems about 10% of players above level 68 or so are playing RF) so for the items that benefit it being expensive, it's just the nature of the game.

Second, players have more money gradually. The longer the league goes on the richer people become and so demand for those high ticket items increases. Initially they start off selling quite cheaply because there are few people who can afford them and so the seller must decrease the price in order to make a quick sale.

Third, the initial prices are made up by the sellers pretty much in each league, starting with something close to what those items used to sell for in past temporary leagues. Then the supply & demand shape it over time according to the popular builds, and whatever is meta in each league. Things are always more expensive because every character and stash tab from temporary leagues gets dumped into the permanent leagues. So there's constant, but slow moving inflation that's only adjusted a little due to supply & demand. Permanent league markets focus more on raw stats to drive prices than the meta of each temporary league. Currency gets devalued while difficult to find, end-game items skyrocket in price provided the market doesn't get flooded with them.

Fourth, at first many players don't even reach end-game or needed items that you listed, but gradually they level up and reache the maps so they would like gain those items you listed. Thus increasing demand. When Demand increases, prices obviously go up. Lower priced items are bought up, and sellers can't list enough on the market, so other sellers are more than happy to list for a little higher. I've only seen this happen for absolute end-game gear and items used to complete challenges in temporary leagues.

Last, increasing of supply is also another potential reason. When Supply increases, prices obviously go down a little because sellers want to list their items closer to the cheapest going prices. But the risk is when you have price fixers intentionally listing low to later grab up other low listings, and keep selling them at a higher price. That's sometimes why new players get frustrated when they PM sellers of the lowest-priced items and don't get replies. It's a mixture of an art form and common sense to know if any one item is being price fixed.

All in all, the reason why prices fluctuate dramatically are varied but the only secret  is that buying at low price and selling at high price. Keep your eyes open to find the most proper moment to buy and sell. Good luck!