Looking a week out I see flights from LGW/LHR/LCY to FRA around £170-180 per person all in.
Cryanair is more like £100 but I don't think this includes all charges. It's impossible to tell without actually booking something.
I also found it difficult to use their site - the captchas they use are very difficult to discern. Took me four goes. I know why they use them, but really is this the best they can do?