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	$118.40	5.607%	$125.0387	$125.04	$125.05	$125.00
Purchase #2	$206.33	13.163%	$233.4892	$233.49	$233.50	$233.50
Purchase #3	$215.90	5.356%	$227.4636	$227.46	$227.45	$227.50
Purchase #4	$113.65	4.425%	$118.679	$118.68	$118.70	$118.70
Purchase #5	$86.77	4.170%	$90.3883	$90.39	$90.40	$90.40
Purchase #6	$67.29	3.366%	$69.555	$69.56	$69.55	$69.60
Purchase #7	$135.60	5.661%	$143.2763	$143.28	$143.30	$143.30
7 purchase totals =	$943.94		$1,007.8901	$1,007.90	$1,007.95	$1,008.00