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	$197.54	8.256%	$213.8489	$213.85	$213.85	$213.80
Purchase #2	$179.89	11.656%	$200.858	$200.86	$200.85	$200.90
Purchase #3	$167.43	12.821%	$188.8962	$188.90	$188.90	$188.90
Purchase #4	$35.77	4.734%	$37.4634	$37.46	$37.45	$37.50
Purchase #5	$158.83	6.206%	$168.687	$168.69	$168.70	$168.70
Purchase #6	$61.43	13.129%	$69.4951	$69.50	$69.50	$69.50
Purchase #7	$137.89	5.741%	$145.8063	$145.81	$145.80	$145.80
7 purchase totals =	$938.78		$1,025.0549	$1,025.07	$1,025.05	$1,025.10