Verizon phones can usually be activated at Page Plus, their prices aren't horrible for pre-paid. Never tried them but have looked them up.
What do you mean 'in a contract with Verizon'? For the D3? You would have to either pay an ETF or put another phone on that line. The D3 would need to be terminated w/Verizon and activated on PP (or whoever), so if it is still under contract you would be charged if you cancel the service on that line.