Question that google is having a surprisingly hard time answering for me:

I have a verizon data plan for the wife and myself. We don't use all of our data each month. I also have a Verizon tablet that has no connected service, I use it on wifi only. Can I add that tablet to my plan without paying an additional monthly fee? The tablet would then consume data out of our pool that I have leftover anyway. I'd like to do this but I'm not sure I like it as much if they want another $10+/mo out of me.

Every time we added a device there was a charge per line. Not sure if that would apply to a tablet, but given how telephone companies work, I am going to say they will get you where ever they can...

You will incur a monthly line fee for a tablet.

Only way you could do that would be to use your phone as a hotspot and use the tablet on WiFi.

This is what I do now just wanted to know if I could avoid the hassle.

It'll be 10 a month for the tablet. I don't see any way around that

No, you can't. Either pony up $10+/mo to add the tablet so it directly accesses your data plan, or keep using your phone as a mobile hot spot so the tablet indirectly accesses the data plan. Either way the outcome is the same, your tablet uses your current data plan. One way you spend an additional $10/mo so you don't have to spend an extra 10 seconds turning on your phone's mobile hotspot (and I guess you could argue you also don't burn through your phone's battery as quickly).   

Thanks guys.  Not the answer I hoped for but the answer I expected.