[support] Calculations in a view

[Unknown]

I need to provide tax calculations as part of a view output.
Views-calc doesn't provide the capability it provides few invariable  
options and I can't seem to get Rewrite Output of a calculation field  
to do the calculation. egs., field_value / 1.1

Civicrm or ubercart seem overkill for our needs.
I need to let applicants enter their donation (not prescribed payments)  
against each of 10 or so events, .
We don't need the complexity of those applications, just to enter  
dollar value donations, sum the totals for each event type and sum the  
total of all incomes and apply tax to some events but not others,  
output the result in a view and as a csv file or spreadsheet.

I have the data entry page working well and views that output results  
and views-calc providing sum and count results but no hope withtax  
calculations.

Can someone point me to a tutorial or module please or show me how to  
code views calc.