Here's a very important note to get out of the way: Customers have to live in a home that has BT Broadband to be eligible for the lowest prices - for everyone else, each contract increases by A 5. So if you've got Virgin, Sky, or TalkTalk, you'd have to change plans to scoop up one of the SIM cards, or pay A 10, A 17, or A 25 instead. So the BT exclusive deals are great extras for existing customers, or further enticements from from the company to sign up as it continues its march to telecoms domination .