Played many game with AH - player shop sys each has there own upside and down side's, I know many all thay do is look for low price's sell high make farly good living in game bye doing so,
Thing's like see, npc would sell back item sold to them simlure to RS sys, Head each npc find potion being sold set bye Dev's - NPC price, Each npc will only sell so many of item's sold to them.
This way making, 1000 of this potion 1000 of this item sold to npc will have sell back shop with some of the item sold to to them so player browes npc buy back shop buy item at npc price.
NPC - Dev based buy back option usly be higher not worth it at time's give's option buy item's that people sell to npc, vs taking time try and spam world
2 nd option, Alowing link of item's in chat
3 rd, Player shop's them self area where player set up shop or comition with npc sys give npc my item when sell's take 20% or so go back npc pick up gold.
AFK sys of player shop never realy work's promte's look of dead game.
AH - Buy low sell high undercuting people never work's, Now make AH - where set time in game player's meet up at the npc give there item to be sold, 1 hr latter AH will start msg will be posted Auction in Edevin will start in 30 min come check out item being sold.
Over all easyer way to sellto player's vs forcing to sell to npc beat point of mmo vs solo player game.
Solo player game where sell item to npc with out option to sell to other for better price's.
MMO mean's player interaction sell of item's so forth