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	$215.45	8.505%	$233.774	$233.77	$233.75	$233.80
Purchase #2	$121.82	3.544%	$126.1373	$126.14	$126.15	$126.10
Purchase #3	$51.30	9.407%	$56.1258	$56.13	$56.15	$56.10
Purchase #4	$183.62	3.732%	$190.4727	$190.47	$190.45	$190.50
Purchase #5	$37.27	3.453%	$38.5569	$38.56	$38.55	$38.60
Purchase #6	$134.43	12.550%	$151.301	$151.30	$151.30	$151.30
Purchase #7	$220.83	3.145%	$227.7751	$227.78	$227.80	$227.80
7 purchase totals =	$964.72		$1,024.1428	$1,024.15	$1,024.15	$1,024.20