Give geospatial search a chance. Use the 'SpatialRecursivePrefixTreeFieldType'
field type, set 'geo' to false.
The date is located on the X-axis, prices on the Y axis.
For every price you get a horizontal line between start and end date. Index a
rectangle with height 0.001(< 1 cent) and width 'end date - start date'.
Find all prices that are valid on a given day or in a given date range with the
'geofilt' function.
The field type could look like (not tested):
<fieldType name="price_date_range"
class="solr.SpatialRecursivePrefixTreeFieldType"
geo="false" distErrPct="0.025" maxDistErr="0.000009" units="degrees"
worldBounds="1 0 366 100000000" />
Faceting possibly can be done with a facet query for every of your price ranges.
For example day 20, price range 0-5$, rectangle: <field name="pdr">20.0 0.0
21.0 5.0</field>.
Regards Holger
