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 $88.37   8.240%   $95.6517   $95.65   $95.65   $95.70  
  Purchase #2 $233.63   5.423%   $246.2998   $246.30   $246.30   $246.30  
  Purchase #3 $197.41   7.695%   $212.6007   $212.60   $212.60   $212.60  
  Purchase #4 $31.93   13.337%   $36.1885   $36.19   $36.20   $36.20  
  Purchase #5 $198.99   7.392%   $213.6993   $213.70   $213.70   $213.70  
  Purchase #6 $194.55   4.446%   $203.1997   $203.20   $203.20   $203.20  
  Purchase #7 $147.29   9.417%   $161.1603   $161.16   $161.15   $161.20  
  7 purchase totals = $1,092.17       $1,168.8000   $1,168.80   $1,168.80   $1,168.90