Statistics to determine low sqft $ for an area

[Brian Davis]

I am looking to automate the collection of $ per sqft data ranges and value ranges by zip code across the country.   I am looking to quickly determine the low price points for a zip code. So if the range of values in a zip code  go from $35,000 to $255,000 for instance, and the bottom 10% of sales average $45,000, how would I go finding this data?  Is this possible?  And also, can I figure out an average low $ per sqft for the average low 10% of sales in that zip code?

Trying to setup some rules and conditions when determining offer prices and something automated would help guide the process for my VA.

Any suggestions or help would be greatly appreciated.  Thanks!