[@Genkai] 
I like the resource management aspect, but its definitely more work for you, since you have to set the price for every purchase. =P 
Speaking from experience though, we should probably have a google doc (or something equivalent) we can all edit for updating group inventory.

But this works out perfectly, since I was wanting to bring in a Merchant-class character! xD

Edit; If you wanted to, you could use the [url=http://www.d20pfsrd.com/equipment/goods-and-services/]goods and services tables[/url] from D&D/Pathfinder as a reference for figuring out how to set prices.