We're currently using our 6620L on Verizon's $65 prepaid unlimited 4G/LTE plan, but I'm planning to order a 7730L soon to get the additional band coverage. I've seen reports of monthly renewal problems with the 8800 on the prepaid plan, but I don't know if that's still current or not. And then there's the lack of 3G fallback for those areas that still have it. Verizon says 3G will be gone next year though, so it won't be an issue for long anyway. We also have AT&T's Connected Car (Mobley) unlimited plan at $20/mo using a Netgear Unite Explore hotspot, and one or the other has worked well everywhere we've been so far. Both plans are subject to priority management on congested towers, but we've never had a noticeable problem with it.
The question was asked about the total price for Verizon's $65 (w/autopay) plan, and the answer is $65. No additional taxes or fees.