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 $87.59   9.420%   $95.841   $95.84   $95.85   $95.80  
  Purchase #2 $57.93   13.193%   $65.5727   $65.57   $65.55   $65.60  
  Purchase #3 $109.80   7.453%   $117.9834   $117.98   $118.00   $118.00  
  Purchase #4 $152.89   3.591%   $158.3803   $158.38   $158.40   $158.40  
  Purchase #5 $194.71   8.469%   $211.2   $211.20   $211.20   $211.20  
  Purchase #6 $203.97   3.321%   $210.7438   $210.74   $210.75   $210.70  
  Purchase #7 $220.25   6.831%   $235.2953   $235.30   $235.30   $235.30  
  7 purchase totals = $1,027.14       $1,095.0165   $1,095.01   $1,095.05   $1,095.00