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	$147.95	13.274%	$167.5889	$167.59	$167.60	$167.60
Purchase #2	$116.56	6.172%	$123.7541	$123.75	$123.75	$123.80
Purchase #3	$45.30	4.336%	$47.2642	$47.26	$47.25	$47.30
Purchase #4	$236.89	7.332%	$254.2588	$254.26	$254.25	$254.30
Purchase #5	$190.42	8.267%	$206.162	$206.16	$206.15	$206.20
Purchase #6	$168.40	4.191%	$175.4576	$175.46	$175.45	$175.50
Purchase #7	$36.27	9.766%	$39.8121	$39.81	$39.80	$39.80
7 purchase totals =	$941.79		$1,014.2977	$1,014.29	$1,014.25	$1,014.50