It looks like Vodafone are doing a Trade-In deal with mobile phones. You can trade your old phones in for a voucher to purchase a new phone (only) at a Vodafone store. If the condition is good, you may get a better deal!
I plan to trade in my Galaxy Note and two other phones for a voucher, and hopefully I can purchase a Galaxy Note 2! Oh and only three phones can be traded in with a maximum combined value of the vouchers: $1500.
You could probably get trading and maybe you will have enough to buy yourself a Galaxy S4! (when it is released!)
More info here.