You can get a subsidized phone when you upgrade. If you aren't eligible for an upgrade, you can't get a subsidized phone. If you want/need a phone, you aren't eligible for an upgrade, and you don't want to pay full retail price through Verizon, you can look to other avenues such as ebay or craigslist.
You have to complete 20 months of your 2yr contract before Verizon will give you another subsidized upgrade. Prior to that, you will have to pay full retail or get the phone from somewhere else, as tikibar1 has mentioned.