just a thought that has come to my attention is that like SlickFic04 said is that the tax would kind of kill specialization. the tax should be like something equivilent not just one item/rune. For example, you said the tax could be a pul rune but what if you dont have a pul rune at the time when the tax is due or what if you do meph runs and only find items.
what i suggest is that the treasurer comes up with a few item equivilents of the tax. And another thing is what would you do with all the pul runes/other tax item of one kind anyway? you said it would be used to help setup tournaments and help new people ect. but atleast to me having 10 or so of the exact same items just doesnt sound logical for trading or even giving away purposes.