The $9.99 is only for days you use plate pass, had to use it for work in DEN. Also had one bad read on my own EZPass during a 2 day rental and they only charged the fee once (was able to get the fee refunded by submitting proof of other transactions during the rental).

The unlimited option is added for each day regardless of usage. Currently $28 at LGA, use it for work also since it's cheaper for a same day round trip to NJ than a personal EZPass.