No, it does not have a Sim Card Slot.
However, if you have a smart phone, most smart phones allow you to tether additional devices to it's 4G Network. I have a Droid Razr Maxx HD and I use it to provide 4G service to my Samsung when I am out in no mans land. Just be sure to monitor your data usage for your cell phone plan because you will be bumming off of it for the tablet.
Other than that, Wi-Fi can be found for free just about anywhere in the public.
If it is the Navigation services you are worried about, the tablet uses aGPS so it only needs Wi-Fi to begin a Navigation and it will retain GPS and Navigation for you until you reach your destination even when you fall out of Wi-Fi. You would only need Wi-Fi if you plan to make any changes to the route and things like that.
The aGPS feature is useful for traveling across long distances, big time!