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 $85.41   11.424%   $95.1672   $95.17   $95.15   $95.20  
  Purchase #2 $208.25   3.383%   $215.2951   $215.30   $215.30   $215.30  
  Purchase #3 $230.77   11.452%   $257.1978   $257.20   $257.20   $257.20  
  Purchase #4 $163.49   8.674%   $177.6711   $177.67   $177.65   $177.70  
  Purchase #5 $96.54   4.651%   $101.0301   $101.03   $101.05   $101.00  
  Purchase #6 $135.66   7.236%   $145.4764   $145.48   $145.50   $145.50  
  Purchase #7 $99.35   4.747%   $104.0661   $104.07   $104.05   $104.10  
  7 purchase totals = $1,019.47       $1,095.9038   $1,095.92   $1,095.90   $1,096.00