How about a gun per month like for one week that it will be sold then around the same month again the gun will back on sale this way People will it will help keep the new player from quiting knowing they could get a cool gun if they still pay for thier account(and if they have the ingame cash)
Ragnarok that only works with whips and rune crap lol
Or if you pked full guthens in one day (amazes me how poeple will take barrows items and pk with them in the wild)