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	$117.38	8.124%	$126.916	$126.92	$126.90	$126.90
Purchase #2	$11.52	8.533%	$12.503	$12.50	$12.50	$12.50
Purchase #3	$38.28	6.141%	$40.6308	$40.63	$40.65	$40.60
Purchase #4	$174.55	10.640%	$193.1221	$193.12	$193.10	$193.10
Purchase #5	$50.60	4.474%	$52.8638	$52.86	$52.85	$52.90
Purchase #6	$127.37	13.208%	$144.193	$144.19	$144.20	$144.20
Purchase #7	$173.98	12.795%	$196.2407	$196.24	$196.25	$196.20
7 purchase totals =	$693.68		$766.4694	$766.46	$766.45	$766.40