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	$89.57	3.549%	$92.7488	$92.75	$92.75	$92.70
Purchase #2	$19.37	7.761%	$20.8733	$20.87	$20.85	$20.90
Purchase #3	$26.69	3.590%	$27.6482	$27.65	$27.65	$27.60
Purchase #4	$187.35	11.313%	$208.5449	$208.54	$208.55	$208.50
Purchase #5	$57.51	3.806%	$59.6988	$59.70	$59.70	$59.70
Purchase #6	$205.53	5.810%	$217.4713	$217.47	$217.45	$217.50
Purchase #7	$120.48	13.143%	$136.3147	$136.31	$136.30	$136.30
7 purchase totals =	$706.50		$763.3000	$763.29	$763.25	$763.20