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	$187.79	4.527%	$196.2913	$196.29	$196.30	$196.30
Purchase #2	$172.96	10.639%	$191.3612	$191.36	$191.35	$191.40
Purchase #3	$211.69	3.521%	$219.1436	$219.14	$219.15	$219.10
Purchase #4	$88.48	4.431%	$92.4005	$92.40	$92.40	$92.40
Purchase #5	$120.74	3.483%	$124.9454	$124.95	$124.95	$124.90
Purchase #6	$40.87	5.777%	$43.2311	$43.23	$43.25	$43.20
Purchase #7	$149.47	3.858%	$155.2366	$155.24	$155.25	$155.20
7 purchase totals =	$972.00		$1,022.6097	$1,022.61	$1,022.65	$1,022.50