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	$213.27	9.330%	$233.1681	$233.17	$233.15	$233.20
Purchase #2	$83.87	9.354%	$91.7152	$91.72	$91.70	$91.70
Purchase #3	$196.54	9.429%	$215.0718	$215.07	$215.05	$215.10
Purchase #4	$44.86	3.224%	$46.3063	$46.31	$46.30	$46.30
Purchase #5	$47.90	3.526%	$49.589	$49.59	$49.60	$49.60
Purchase #6	$164.55	5.287%	$173.2498	$173.25	$173.25	$173.20
Purchase #7	$200.89	7.810%	$216.5795	$216.58	$216.60	$216.60
7 purchase totals =	$951.88		$1,025.6797	$1,025.69	$1,025.65	$1,025.70