Only if you have an unlimited minute plan. Otherwise it's likely you just have unlimited "in calling" which means in network. So only if they also have a verizon wireless cell phone.
No incoming calls are free. Regardless of the source.
However, depending on the plan that you are on and the time of the call, they may or may not get charged against your minute limit.
Verizon "Mobile to Mobile" calls typically do not count against the limit. This would include incoming and outgoing.
Friends and Family calls (if you are still on a plan that has that) would not count against the limit. Incoming and outgoing.
And of course, if you have an unlimited minutes plan, there would be no charge.
So, the question would be, what plan are you on?