So in OSRS if you finish a certain diary, a NPC gathers battlestaffs for you to go and collect. Since we do not have any diaries there should be a simulator used with GP. For a slight example, Blast Furnace, with GP you get time to use that for xp. The simulator should be a certain amount of battlestaffs gathered overtime, and the more money you put into this the longer the battlestaffs will be spawned that you can collect after the time is up.