dont give out item's until you get more players then you give out like 1 item maybe 2-3 and people will go nuts to try to get it which causes prices to soar.
make all drops come from bandos, nex, arma, zammy etc so they have to get the drops from npc's someone will have money and someone will have the item they want and they will buy it for whatever the price the guy is willing to sell it for... but the biggest thing DO NOT GIVE OUT ITEMS if you give out items they end up having too many of that item and then prices get fucked. i gave out a few agses on my server and next thing you know ags is 50-100m and bandos is 1b