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 $86.51   9.758%   $94.9516   $94.95   $94.95   $95.00  
  Purchase #2 $169.34   7.222%   $181.5697   $181.57   $181.55   $181.60  
  Purchase #3 $189.35   3.485%   $195.9488   $195.95   $195.95   $195.90  
  Purchase #4 $82.80   7.283%   $88.8303   $88.83   $88.85   $88.80  
  Purchase #5 $185.51   8.463%   $201.2097   $201.21   $201.20   $201.20  
  Purchase #6 $132.71   6.772%   $141.6971   $141.70   $141.70   $141.70  
  Purchase #7 $217.35   6.204%   $230.8344   $230.83   $230.85   $230.80  
  7 purchase totals = $1,063.57       $1,135.0416   $1,135.04   $1,135.05   $1,135.00