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	$79.86	3.497%	$82.6527	$82.65	$82.65	$82.70
Purchase #2	$117.25	8.520%	$127.2397	$127.24	$127.25	$127.20
Purchase #3	$159.38	9.409%	$174.3761	$174.38	$174.40	$174.40
Purchase #4	$137.70	6.565%	$146.74	$146.74	$146.75	$146.70
Purchase #5	$202.55	6.446%	$215.6064	$215.61	$215.60	$215.60
Purchase #6	$154.96	11.304%	$172.4767	$172.48	$172.50	$172.50
Purchase #7	$102.31	4.178%	$106.5845	$106.58	$106.60	$106.60
7 purchase totals =	$954.01		$1,025.6761	$1,025.68	$1,025.75	$1,025.70