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	$148.27	3.178%	$152.982	$152.98	$153.00	$153.00
Purchase #2	$110.31	8.725%	$119.9345	$119.93	$119.95	$119.90
Purchase #3	$94.86	11.369%	$105.6446	$105.64	$105.65	$105.60
Purchase #4	$237.64	10.257%	$262.0147	$262.01	$262.00	$262.00
Purchase #5	$136.48	11.106%	$151.6375	$151.64	$151.65	$151.60
Purchase #6	$123.76	10.306%	$136.5147	$136.51	$136.50	$136.50
Purchase #7	$110.26	5.862%	$116.7234	$116.72	$116.70	$116.70
7 purchase totals =	$961.58		$1,045.4514	$1,045.43	$1,045.45	$1,045.30