I have just looked at a few sites in the lakes, incase my memory failed me from looking last year when our friends stayed in one. £40 seems about the average.
I think the other thing to consider is what they offer with your pod. We stayed in a pod with no electric and it claimed to have lighting, but it was rubbish and we'd left all of our lanterns at home. We were given a gas cylinder heater but told to leave the window open otherwise lack of oxygen would make it go out. If that didn't scare us enough we realised that when we rolled out the beds there was only about a foot between us and the door to put the heater in. We were glad we tried it but wouldn't do it again. We stayed in a Wigwam with electric and it was brilliant. I took the husband who won't do a tent.