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	$219.53	11.550%	$244.8857	$244.89	$244.90	$244.90
Purchase #2	$135.31	4.122%	$140.8875	$140.89	$140.90	$140.90
Purchase #3	$130.41	11.647%	$145.5989	$145.60	$145.60	$145.60
Purchase #4	$21.36	10.532%	$23.6096	$23.61	$23.60	$23.60
Purchase #5	$72.30	8.473%	$78.426	$78.43	$78.45	$78.40
Purchase #6	$201.43	7.848%	$217.2382	$217.24	$217.25	$217.20
Purchase #7	$168.64	3.566%	$174.6537	$174.65	$174.65	$174.70
7 purchase totals =	$948.98		$1,025.2996	$1,025.31	$1,025.35	$1,025.30