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	$168.73	3.685%	$174.9477	$174.95	$174.95	$174.90
Purchase #2	$161.47	6.558%	$172.0592	$172.06	$172.05	$172.10
Purchase #3	$205.56	5.599%	$217.0693	$217.07	$217.05	$217.10
Purchase #4	$221.66	4.118%	$230.788	$230.79	$230.80	$230.80
Purchase #5	$202.79	13.128%	$229.4123	$229.41	$229.40	$229.40
Purchase #6	$90.52	5.554%	$95.5475	$95.55	$95.55	$95.50
Purchase #7	$11.25	3.508%	$11.6447	$11.64	$11.65	$11.60
7 purchase totals =	$1,061.98		$1,131.4687	$1,131.47	$1,131.45	$1,131.40