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	$113.28	11.181%	$125.9458	$125.95	$125.95	$125.90
Purchase #2	$125.66	9.412%	$137.4871	$137.49	$137.50	$137.50
Purchase #3	$223.76	5.137%	$235.2546	$235.25	$235.25	$235.30
Purchase #4	$236.78	11.759%	$264.623	$264.62	$264.60	$264.60
Purchase #5	$29.72	9.575%	$32.5657	$32.57	$32.55	$32.60
Purchase #6	$103.52	7.764%	$111.5573	$111.56	$111.55	$111.60
Purchase #7	$249.91	12.419%	$280.9463	$280.95	$280.95	$280.90
7 purchase totals =	$1,082.63		$1,188.3798	$1,188.39	$1,188.35	$1,188.40