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	$195.86	9.530%	$214.5255	$214.53	$214.55	$214.50
Purchase #2	$76.63	8.305%	$82.9941	$82.99	$83.00	$83.00
Purchase #3	$180.66	5.443%	$190.4933	$190.49	$190.50	$190.50
Purchase #4	$103.30	3.274%	$106.682	$106.68	$106.70	$106.70
Purchase #5	$59.94	12.712%	$67.5596	$67.56	$67.55	$67.60
Purchase #6	$206.73	3.476%	$213.9159	$213.92	$213.90	$213.90
Purchase #7	$189.71	10.301%	$209.252	$209.25	$209.25	$209.30
7 purchase totals =	$1,012.83		$1,085.4224	$1,085.42	$1,085.45	$1,085.50