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 $195.41   5.553%   $206.2611   $206.26   $206.25   $206.30  
  Purchase #2 $192.89   13.252%   $218.4518   $218.45   $218.45   $218.50  
  Purchase #3 $25.69   5.158%   $27.0151   $27.02   $27.00   $27.00  
  Purchase #4 $182.35   5.148%   $191.7374   $191.74   $191.75   $191.70  
  Purchase #5 $164.84   3.522%   $170.6457   $170.65   $170.65   $170.60  
  Purchase #6 $154.71   9.432%   $169.3022   $169.30   $169.30   $169.30  
  Purchase #7 $180.62   9.431%   $197.6543   $197.65   $197.65   $197.70  
  7 purchase totals = $1,096.51       $1,181.0676   $1,181.07   $1,181.05   $1,181.10