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 $69.86   8.859%   $76.0489   $76.05   $76.05   $76.00  
  Purchase #2 $93.79   11.264%   $104.3545   $104.35   $104.35   $104.40  
  Purchase #3 $75.58   10.666%   $83.6414   $83.64   $83.65   $83.60  
  Purchase #4 $228.99   8.149%   $247.6504   $247.65   $247.65   $247.70  
  Purchase #5 $189.78   8.161%   $205.2679   $205.27   $205.25   $205.30  
  Purchase #6 $208.76   3.665%   $216.4111   $216.41   $216.40   $216.40  
  Purchase #7 $145.97   10.736%   $161.6413   $161.64   $161.65   $161.60  
  7 purchase totals = $1,012.73       $1,095.0155   $1,095.01   $1,095.00   $1,095.00