Every year TFP always has a thread started with bleach prices posted by various users. Rather than in a sequential thread, this kind of data would be perfect for mapping (bleach prices/quantities/strengths/retailer by zip codes). One could even think of expanding this to other useful chemicals like MA or baking soda. There is software out there for doing these types of graphical overlays but I have no feel for how this data could be mined from the TFP website or if it's worth the cost. It's definitely not a manual data entry job, a database agent would have to be programmed to mine the data each day or a separate input panel would be needed to allow users to enter purchases they have made.
Just a wacky thought and wondering if an idea like this was ever discussed. As an SWCG operator, my bleach consumption in a season is minimal compared to those who manually dose or those who run Stenner pumps. It would be a useful resource for those needing to SLAM as they could then get an up-to-date view of how much it might cost them and where they can get the best price.