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	$43.46	9.142%	$47.4331	$47.43	$47.45	$47.40
Purchase #2	$119.57	3.258%	$123.4656	$123.47	$123.45	$123.50
Purchase #3	$149.31	3.766%	$154.933	$154.93	$154.95	$154.90
Purchase #4	$241.96	8.110%	$261.583	$261.58	$261.60	$261.60
Purchase #5	$198.47	12.758%	$223.7908	$223.79	$223.80	$223.80
Purchase #6	$155.67	7.373%	$167.1475	$167.15	$167.15	$167.10
Purchase #7	$59.43	11.418%	$66.2157	$66.22	$66.20	$66.20
7 purchase totals =	$967.87		$1,044.5687	$1,044.57	$1,044.60	$1,044.50