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 $87.38   8.772%   $95.045   $95.05   $95.05   $95.00  
  Purchase #2 $153.64   4.539%   $160.6137   $160.61   $160.60   $160.60  
  Purchase #3 $98.29   4.366%   $102.5813   $102.58   $102.60   $102.60  
  Purchase #4 $162.84   11.491%   $181.5519   $181.55   $181.55   $181.60  
  Purchase #5 $117.34   4.330%   $122.4208   $122.42   $122.40   $122.40  
  Purchase #6 $241.31   3.188%   $249.003   $249.00   $249.00   $249.00  
  Purchase #7 $240.71   8.872%   $262.0658   $262.07   $262.05   $262.10  
  7 purchase totals = $1,101.51       $1,173.2815   $1,173.28   $1,173.25   $1,173.30