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 $184.70   5.550%   $194.9509   $194.95   $194.95   $195.00  
  Purchase #2 $8.58   10.208%   $9.4558   $9.46   $9.45   $9.50  
  Purchase #3 $115.46   3.132%   $119.0762   $119.08   $119.10   $119.10  
  Purchase #4 $248.89   7.436%   $267.3975   $267.40   $267.40   $267.40  
  Purchase #5 $189.89   6.449%   $202.136   $202.14   $202.15   $202.10  
  Purchase #6 $35.49   13.238%   $40.1882   $40.19   $40.20   $40.20  
  Purchase #7 $250.33   4.601%   $261.8477   $261.85   $261.85   $261.80  
  7 purchase totals = $1,033.34       $1,095.0523   $1,095.07   $1,095.10   $1,095.10