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	$239.85	9.341%	$262.2544	$262.25	$262.25	$262.30
Purchase #2	$86.92	7.863%	$93.7545	$93.75	$93.75	$93.80
Purchase #3	$166.68	9.262%	$182.1179	$182.12	$182.10	$182.10
Purchase #4	$24.27	4.410%	$25.3403	$25.34	$25.35	$25.30
Purchase #5	$171.89	9.221%	$187.74	$187.74	$187.75	$187.70
Purchase #6	$84.61	5.664%	$89.4023	$89.40	$89.40	$89.40
Purchase #7	$174.52	12.849%	$196.9441	$196.94	$196.95	$196.90
7 purchase totals =	$948.74		$1,037.5535	$1,037.54	$1,037.55	$1,037.50