After a bit of scouting ebay i've found that £300 is the average price.
I could just buy one then sell whatever upgrade i get in 6 months but i'd prefer to try something a little easier.
Could i sign a new contract with vodafone on a £27 package for 18 months and pay £100 for the phone and put my current number on it, then put the new number on the contract i've got with 6 months left. Then when the 6months is up i just don't renew the contract because i've got my old number on my new phone/contract.
Hope i've explained it ok, would vodafone allow this?