Price Policy coffeescript updates

This addresses two issues from the previous change (and obsoletes PR #131):

* Subsidies should apply to a single policy row and not affect others
* Minimum cost values should be to the penny

Still outstanding: subsidized minimum costs display just as values, not as calculations (that is: "$80.00" instead of something along the lines of "$100.00 - $20.00 subsidy = $80.00")