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	$175.32	8.450%	$190.1345	$190.13	$190.15	$190.10
Purchase #2	$21.34	10.561%	$23.5937	$23.59	$23.60	$23.60
Purchase #3	$101.51	5.150%	$106.7378	$106.74	$106.75	$106.70
Purchase #4	$195.96	13.432%	$222.2813	$222.28	$222.30	$222.30
Purchase #5	$50.39	8.257%	$54.5507	$54.55	$54.55	$54.60
Purchase #6	$158.92	8.854%	$172.9908	$172.99	$173.00	$173.00
Purchase #7	$240.82	6.229%	$255.8207	$255.82	$255.80	$255.80
7 purchase totals =	$944.26		$1,026.1095	$1,026.10	$1,026.15	$1,026.10