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 $87.75   9.355%   $95.959   $95.96   $95.95   $96.00  
  Purchase #2 $23.46   10.607%   $25.9484   $25.95   $25.95   $25.90  
  Purchase #3 $13.30   9.543%   $14.5692   $14.57   $14.55   $14.60  
  Purchase #4 $22.68   13.356%   $25.7091   $25.71   $25.70   $25.70  
  Purchase #5 $87.30   9.573%   $95.6572   $95.66   $95.65   $95.70  
  Purchase #6 $213.86   9.539%   $234.2601   $234.26   $234.25   $234.30  
  Purchase #7 $214.54   9.569%   $235.0693   $235.07   $235.05   $235.10  
  7 purchase totals = $662.89       $727.1723   $727.18   $727.10   $727.30