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	$199.31	5.243%	$209.7598	$209.76	$209.75	$209.80
Purchase #2	$12.38	7.208%	$13.2724	$13.27	$13.25	$13.30
Purchase #3	$88.84	8.811%	$96.6677	$96.67	$96.65	$96.70
Purchase #4	$6.71	9.600%	$7.3542	$7.35	$7.35	$7.40
Purchase #5	$142.32	5.872%	$150.677	$150.68	$150.70	$150.70
Purchase #6	$51.59	4.687%	$54.008	$54.01	$54.00	$54.00
Purchase #7	$181.43	8.333%	$196.5486	$196.55	$196.55	$196.50
7 purchase totals =	$682.58		$728.2877	$728.29	$728.25	$728.40