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	$41.87	4.844%	$43.8982	$43.90	$43.90	$43.90
Purchase #2	$48.33	4.500%	$50.5049	$50.50	$50.50	$50.50
Purchase #3	$80.67	6.855%	$86.1999	$86.20	$86.20	$86.20
Purchase #4	$68.43	6.452%	$72.8451	$72.85	$72.85	$72.80
Purchase #5	$182.76	5.201%	$192.2653	$192.27	$192.25	$192.30
Purchase #6	$89.61	3.658%	$92.8879	$92.89	$92.90	$92.90
Purchase #7	$164.74	13.632%	$187.1974	$187.20	$187.20	$187.20
7 purchase totals =	$676.41		$725.7987	$725.81	$725.80	$725.80