It is hard to tell if you don't provide any information about which plan you have now. If you have a current plan, you can see how much a connected tablet will be per month at https://www.verizonwireless.com/plans/unlimited/ and compare the plan options.
I'm most definitely NOT a VZW employee. If a post answered your question, please mark it as the answer.
$10 if you have a data package, $20 if you have unlimited. (Do More and Get More Unlimited gives you a 50% discount on tablets making them $10 instead of $20)
Definitely not "free" as many lying sales reps will lead you to believe.