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	$181.51	7.423%	$194.9835	$194.98	$195.00	$195.00
Purchase #2	$139.52	10.137%	$153.6631	$153.66	$153.65	$153.70
Purchase #3	$188.73	5.362%	$198.8497	$198.85	$198.85	$198.80
Purchase #4	$95.85	4.475%	$100.1393	$100.14	$100.15	$100.10
Purchase #5	$112.32	6.792%	$119.9488	$119.95	$119.95	$119.90
Purchase #6	$78.92	12.755%	$88.9862	$88.99	$89.00	$89.00
Purchase #7	$215.77	13.156%	$244.1567	$244.16	$244.15	$244.20
7 purchase totals =	$1,012.62		$1,100.7273	$1,100.73	$1,100.75	$1,100.70