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	$72.98	5.433%	$76.945	$76.95	$76.95	$76.90
Purchase #2	$74.69	5.405%	$78.727	$78.73	$78.75	$78.70
Purchase #3	$200.50	5.613%	$211.7541	$211.75	$211.75	$211.80
Purchase #4	$18.32	4.808%	$19.2008	$19.20	$19.20	$19.20
Purchase #5	$243.56	12.422%	$273.815	$273.82	$273.80	$273.80
Purchase #6	$78.46	10.256%	$86.5069	$86.51	$86.50	$86.50
Purchase #7	$248.43	4.444%	$259.4702	$259.47	$259.45	$259.50
7 purchase totals =	$936.94		$1,006.4190	$1,006.43	$1,006.40	$1,006.40