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	$177.52	10.677%	$196.4738	$196.47	$196.45	$196.50
Purchase #2	$6.95	4.770%	$7.2815	$7.28	$7.30	$7.30
Purchase #3	$250.43	10.202%	$275.9789	$275.98	$276.00	$276.00
Purchase #4	$137.63	8.459%	$149.2721	$149.27	$149.25	$149.30
Purchase #5	$69.95	3.803%	$72.6102	$72.61	$72.60	$72.60
Purchase #6	$132.86	9.838%	$145.9308	$145.93	$145.95	$145.90
Purchase #7	$234.64	10.303%	$258.815	$258.82	$258.80	$258.80
7 purchase totals =	$1,009.98		$1,106.3623	$1,106.36	$1,106.35	$1,106.40