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 $43.83   7.115%   $46.9485   $46.95   $46.95   $46.90  
  Purchase #2 $67.43   11.153%   $74.9505   $74.95   $74.95   $75.00  
  Purchase #3 $174.97   8.170%   $189.265   $189.27   $189.25   $189.30  
  Purchase #4 $185.43   10.472%   $204.8482   $204.85   $204.85   $204.80  
  Purchase #5 $122.87   8.466%   $133.2722   $133.27   $133.25   $133.30  
  Purchase #6 $233.42   6.360%   $248.2655   $248.27   $248.25   $248.30  
  Purchase #7 $179.27   10.584%   $198.2439   $198.24   $198.25   $198.20  
  7 purchase totals = $1,007.22       $1,095.7938   $1,095.80   $1,095.75   $1,095.80