I've several toons that I use at varying times (dependant on lag) and the lower end ones usually pick up items that are useful to new and lower level players. Because they are not worth masses (not rare, C upwards or +'d beyond 3) I tend to just go to the store and check the offer price then sell it at 2 and a half times what they offer as I've heard they normally offer to buy at around a third of its true value. Is this right? I'm not too worried about making masses as I cant really with this kind of stock but I neither want to overcharge (not wanting to rip off the lower lvls) not under charge (rip myself off). Does anyone else use any other method?
Checking against the other sellers isn't really necessary for me, I'm not overly fussed about playing the markets with low levels, just selling my stock.
It depends on the item. If it's a set-completing item that isn't sold at the store (e.g. Elven Mithril Gloves, Boots of Knowledge and Brig Helm), you need to find out what the market price is, because some of these go for quite a bit of money. For items that are sold in the store, I usually just sell for crystal price, or even a bit lower.
Well I check other players or check the store and sell for 2x the amount. It also depends on what it is, some things are worth more because they are rare and some are worth even less because no one uses that item.
NPC shops will buy items for 1/2 the price they will sell you the same items for. to check this (i could be wrong) look at the price of a scroll of escape and look at what the store will buy it for. that said, the NPC stores will buy some things from you for absurdly low prices (for some quest items 0 adena >.<) such as quest items and enchant scrolls. try poking around to find something similar in another shop, or use the website to find out the # of crystals the item is worth, figure 700 for D grade crystals, 3k for C grade crystals. top-grade stuff however, goes for more than crystal price.