I dont see how much further prices can drop. It would seem that people want something for nothing but what would be the point in that. If prices are too low then any company would find that unsustainable. Good luck to giffgaff and I for one am very very happy with the service I receive for what I consider to be a fair price. I would however be interested to see how long the payback will go on for. Without knowing the breakdown costs of running a network I wouldnt be able to comment but make hay while the sun shines. It would be interesting to know across the spectrum of customers giffgaff has, how many percentage wise benefit from pay back. Aside from introducing the odd new customer how many actually participate in the online forum? If its only a small percentage then perhaps giffgaff can keep the payback going indefinately but if every single customer decided to go for payback by actively taking part would giffgaff still be able to afford it? Time will tell.