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	$111.50	13.445%	$126.4912	$126.49	$126.50	$126.50
Purchase #2	$24.49	4.271%	$25.536	$25.54	$25.55	$25.50
Purchase #3	$81.31	4.603%	$85.0527	$85.05	$85.05	$85.10
Purchase #4	$217.77	11.870%	$243.6193	$243.62	$243.60	$243.60
Purchase #5	$131.66	11.690%	$147.0511	$147.05	$147.05	$147.10
Purchase #6	$168.44	8.753%	$183.1836	$183.18	$183.20	$183.20
Purchase #7	$207.28	3.503%	$214.541	$214.54	$214.55	$214.50
7 purchase totals =	$942.45		$1,025.4749	$1,025.47	$1,025.50	$1,025.50