Let's do some math ..  Rounding examples of 7 random hypothetical purchases:
  Case Tag  
Price  
Sales  
Tax %  
Raw Total  
Incl. Sales Tax  
Rounded  
to Penny  
Rounded  
to Nickel  
Rounded  
to Dime  
  Purchase #1 $86.68   10.173%   $95.498   $95.50   $95.50   $95.50  
  Purchase #2 $211.28   8.189%   $228.5817   $228.58   $228.60   $228.60  
  Purchase #3 $233.54   9.493%   $255.71   $255.71   $255.70   $255.70  
  Purchase #4 $63.33   8.797%   $68.9011   $68.90   $68.90   $68.90  
  Purchase #5 $122.28   3.374%   $126.4057   $126.41   $126.40   $126.40  
  Purchase #6 $185.80   10.157%   $204.6717   $204.67   $204.65   $204.70  
  Purchase #7 $180.56   4.768%   $189.1691   $189.17   $189.15   $189.20  
  7 purchase totals = $1,083.47       $1,168.9373   $1,168.94   $1,168.90   $1,169.00