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	$125.27	7.455%	$134.6089	$134.61	$134.60	$134.60
Purchase #2	$49.38	4.127%	$51.4179	$51.42	$51.40	$51.40
Purchase #3	$87.58	5.483%	$92.382	$92.38	$92.40	$92.40
Purchase #4	$92.72	3.530%	$95.993	$95.99	$96.00	$96.00
Purchase #5	$248.40	6.664%	$264.9534	$264.95	$264.95	$265.00
Purchase #6	$148.70	10.615%	$164.4845	$164.48	$164.50	$164.50
Purchase #7	$250.55	7.589%	$269.5642	$269.56	$269.55	$269.60
7 purchase totals =	$1,002.60		$1,073.4039	$1,073.39	$1,073.40	$1,073.50