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	$211.28	3.738%	$219.1776	$219.18	$219.20	$219.20
Purchase #2	$250.34	5.243%	$263.4653	$263.47	$263.45	$263.50
Purchase #3	$222.59	11.640%	$248.4995	$248.50	$248.50	$248.50
Purchase #4	$25.37	11.838%	$28.3733	$28.37	$28.35	$28.40
Purchase #5	$96.50	9.331%	$105.5044	$105.50	$105.50	$105.50
Purchase #6	$14.38	3.468%	$14.8787	$14.88	$14.90	$14.90
Purchase #7	$127.76	5.348%	$134.5926	$134.59	$134.60	$134.60
7 purchase totals =	$948.22		$1,014.4914	$1,014.49	$1,014.50	$1,014.60