Amazon and O2 obviously established something of a rapport while working together on the UK launch of the Fire phone. Today, the pair solidify their alliance, with Amazon taking on a new role as an O2 contract reseller. The online retail giant spins it a little differently, saying you can now use its site to shop for the latest smartphones on pay-monthly contracts. With only O2 providing the contracts, though, it's six and two threes. Anywho, Amazon's "Phones & Accessories" store has been updated to include these new pay-monthly options alongside the existing SIM-free and pay-as-you-go handsets (which are available through multiple carriers). And to celebrate, several introductory deals are being offered to new and upgrading O2 customers. For a limited time, the Microsoft Lumia 735, Huawei Ascend P7 and HTC One M8 are free on contracts of £15, £20 and £28 per month, respectively. Amazon's also keen to point out you can now buy its Fire phone direct from the source for the first time -- because please buy Fire phone.