This is a modification of the standard Customer Product Sales Report extended to show fixed and unit costs and prices.
*** Added back ported 1.8 version 18Feb17
*** Updated 8Feb17 to add overall totals and show 0.01 quantities

The parameter screen is:

Sample output is (with Print Detail checked):

or without Print Detail checked:

The Explanatory text is:
This report shows which products were sold during the specified period (and if details are requested, then to which customers).
The period is inclusive - ie sales from 00:00 on the start date through 23:59:59 on the end date.
The totals are the total of all invoices less any credits but does not include adjustments.
All the selection fields entered have % added so that leaving them blank will find all, and entering say product %vacc will find all products contain 'vacc' in their product name, and customer fred will find Fred, Fredricks, Freddy, etc. Note that these are case insensitive. If you just want counter sales, set the Customer to %counter sale.
For Product Type and Classification (Product Group and Product Income Type) selection, omitting the selection will include products with no product type or classification respectively, and using the selection '-' will find only those with no product type or classification.
All amounts are tax inclusive.
The Unit Cost column numbers are extended, ie what is shown is Unit Cost x Quantity. Ditto for the Unit Amount column.
NOTE that the cost and amount information is taken from the invoice (and credit) line items and not from the product price data.  Hence it reflects the costing and pricing at the time of the sale rather than the current cost and pricing.