Firstly, you have a nice friend. Ummm, I don't think you are ever required to sign a contract just to use a phone. Signing a contract enables you to purchase a new phone at a discount. However, if you already own a phone with a clean ESN, you should be able to activate it after choosing your voice, text, and data plan. Then you simply pay month to month. You can easily do this online if you already have a new, unused SIM card. If you need a SIM card, you can pick one up at a Verizon store for a small price.
As you use the phone, you can change your plan to increase or decrease the data amount should you need to. But you can quit using Verizon at any time since you are not under a contract. The only requirement to use the Razr Maxx would be that you have to have a data plan to use an LTE smartphone on Verizon.
I don't think you'll be able to get a $50 total bill plan, though. It looks like the voice and text only come as an unlimited $40 plan, plus the minimum data plan is 1 gigabytes for $50.
So the voice, text, and data will be a minimum of $90 per month, plus any taxes and other communications fees. You are looking at around $95 to $100 per month for your actual bill. No contract, though.
I have tried to activate my Droid Razr MAXX online for the prepaid plan, and I keep getting told that this phone isn't eligible for the prepaid because it is a 4G phone. If you have a solution as to how I can get this phone activated, I would LOVE to hear it! I would appreciate the help