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	$214.59	9.330%	$234.6112	$234.61	$234.60	$234.60
Purchase #2	$146.26	4.265%	$152.498	$152.50	$152.50	$152.50
Purchase #3	$183.96	11.763%	$205.5992	$205.60	$205.60	$205.60
Purchase #4	$83.45	8.129%	$90.2337	$90.23	$90.25	$90.20
Purchase #5	$159.70	5.469%	$168.434	$168.43	$168.45	$168.40
Purchase #6	$91.79	13.575%	$104.2505	$104.25	$104.25	$104.30
Purchase #7	$186.70	6.663%	$199.1398	$199.14	$199.15	$199.10
7 purchase totals =	$1,066.45		$1,154.7664	$1,154.76	$1,154.80	$1,154.70