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 $59.79   3.616%   $61.952   $61.95   $61.95   $62.00  
  Purchase #2 $131.41   13.573%   $149.2463   $149.25   $149.25   $149.20  
  Purchase #3 $47.84   4.172%   $49.8359   $49.84   $49.85   $49.80  
  Purchase #4 $200.25   7.478%   $215.2247   $215.22   $215.20   $215.20  
  Purchase #5 $190.30   7.673%   $204.9017   $204.90   $204.90   $204.90  
  Purchase #6 $248.99   4.135%   $259.2857   $259.29   $259.30   $259.30  
  Purchase #7 $194.87   13.372%   $220.928   $220.93   $220.95   $220.90  
  7 purchase totals = $1,073.45       $1,161.3743   $1,161.38   $1,161.40   $1,161.30