In the United Kingdom, O2, EE, 3, Vodafone, and Tesco Mobile sell the device under subsidized contracts, or for use on a pay as you go. They are locked to the network initially, though they can usually be unlocked either after a certain period of contract length has passed, or for a small fee (with the exception of the 3 network, which will unlock the device at any time for no charge).[214] However, all current versions of iPhone are available for purchase SIM-free from the Apple Store or Apple's Online Store, consequently, they are unlocked for use on any GSM network too.[215][unreliable source?]