Do you use GROUPON? So far, with my limited experience, I have found them to be very trustworthy. https://www.groupon.com/coupons/stores/verizonwireless.com
I have Verizon as my cell phone provider and I am happy with their associates and overall corporation. I will not be trading in my brand new iPhone 5S+ as I just got it and I got it so I can use the HUM GPS equipment
Two places for HUM information:
https://www.hum.com/ or http://www.verizon.com/about/news/verizon-announces-availability-hum-creating-smart-connected-driving-experience-more-150-million
or possibly a third option which State Farm Insurance has offered for several years, which is similar to the HUM system, and I have enrolled in this program, however, I have not yet received the equipment. Of course, the insurance company will be keeping track of my driving, and is they deem it is unsafe, they will increase my rates or drop me.