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	$83.96	13.214%	$95.0545	$95.05	$95.05	$95.10
Purchase #2	$240.41	6.215%	$255.3515	$255.35	$255.35	$255.40
Purchase #3	$202.51	10.432%	$223.6358	$223.64	$223.65	$223.60
Purchase #4	$18.60	12.475%	$20.9204	$20.92	$20.90	$20.90
Purchase #5	$153.70	10.279%	$169.4988	$169.50	$169.50	$169.50
Purchase #6	$214.31	3.443%	$221.6887	$221.69	$221.70	$221.70
Purchase #7	$113.79	5.176%	$119.6798	$119.68	$119.70	$119.70
7 purchase totals =	$1,027.28		$1,105.8295	$1,105.83	$1,105.85	$1,105.90