You know about Envirofone. You send them your old handset, they give you money.
Who buys the phones? Well, you guys can. Head to the Envirofone Shop and you can get second-hand phones which have been professionally refurbished and come with a 6 month warranty. Some are still locked, but that’s an easy enough obstacle to overcome. Also, the price of the handset depends on the condition. If it has a few scratches then it’ll be cheaper. As an example, a “B rated” iPhone 6 Plus (16GB Three model) is £540, and a 16GB EE iPhone 6 is £429.
Yes, they might still seem a bit expensive, but do the maths – a “B” rated iPhone 6 is £540, which would be £22.50 per month if you paid for it over 2 years. Add a SIM-only deal onto that and you could be quids in.