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	$107.56	6.767%	$114.8386	$114.84	$114.85	$114.80
Purchase #2	$8.56	3.385%	$8.8498	$8.85	$8.85	$8.80
Purchase #3	$104.52	3.803%	$108.4949	$108.49	$108.50	$108.50
Purchase #4	$101.32	11.390%	$112.8603	$112.86	$112.85	$112.90
Purchase #5	$42.30	12.331%	$47.516	$47.52	$47.50	$47.50
Purchase #6	$35.72	7.769%	$38.4951	$38.50	$38.50	$38.50
Purchase #7	$11.93	13.498%	$13.5403	$13.54	$13.55	$13.50
7 purchase totals =	$411.91		$444.5950	$444.60	$444.60	$444.50