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	$119.72	6.449%	$127.4407	$127.44	$127.45	$127.40
Purchase #2	$11.88	8.224%	$12.857	$12.86	$12.85	$12.90
Purchase #3	$221.67	6.498%	$236.0741	$236.07	$236.05	$236.10
Purchase #4	$241.74	8.555%	$262.4209	$262.42	$262.40	$262.40
Purchase #5	$165.35	9.590%	$181.2071	$181.21	$181.20	$181.20
Purchase #6	$164.53	13.279%	$186.3779	$186.38	$186.40	$186.40
Purchase #7	$141.50	13.703%	$160.8897	$160.89	$160.90	$160.90
7 purchase totals =	$1,066.39		$1,167.2674	$1,167.27	$1,167.25	$1,167.30