This is from the Sam's Club website. Make sure you are looking at the "upgrade" price at Sam's and not the New Customer price. I think you have to go in there and they look up your Verizon account and tell you what you are eligible for and what it will cost, the same as if you go to any of those authorized dealers at a kiosk at the mall. This says you have to sign up for another 2 year agreement, not sure what deal you got thru Verizon directly.
Am I Eligible for a Verizon Wireless Cell Phone Upgrade?
Not all existing Verizon Wireless customers qualify for contract extensions. Verizon Wireless alone sets threshold rules as to who is eligible for a contract extension, as follows:
You must be at least 11 months into your 1 year contract, or 22 months into your 2 year contract.
Your account must be in good financial standing and without late fees.
You agree to extend your contract 24 months from the end of your existing contract.
If you extend your contract length on a family plan for a single phone, all lines of service will be extended to the new contract end date of the upgraded phone line.
Note that eligibility results may vary based on a variety of conditions including, but not limited to a customer's usage history, payment record, previous phone replacement, etc. Upgrade eligibility is determined by Verizon Wireless in its sole discretion. Account approval will vary.