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	$195.41	10.401%	$215.7346	$215.73	$215.75	$215.70
Purchase #2	$6.91	5.351%	$7.2798	$7.28	$7.30	$7.30
Purchase #3	$75.58	4.238%	$78.7831	$78.78	$78.80	$78.80
Purchase #4	$98.38	5.742%	$104.029	$104.03	$104.05	$104.00
Purchase #5	$162.63	3.214%	$167.8569	$167.86	$167.85	$167.90
Purchase #6	$184.65	13.574%	$209.7144	$209.71	$209.70	$209.70
Purchase #7	$178.79	7.851%	$192.8268	$192.83	$192.85	$192.80
7 purchase totals =	$902.35		$976.2246	$976.22	$976.30	$976.20