I don't know how Wizz make a profit with a 50 pound return trip of around 2000 miles not to mention the 30 pound fare. So at 30 pounds that's 1,5 pence per mile.Wizz must be doing something right or they would have gone bust by now.
The same as how Ryanair make profit on £10 fares: yield management. £50 will only be the cheapest fare available, if booked well in advance. The closer you get to the flight, or as the aircraft fills up, the more expensive the flight gets. If I want to travel DSA-Katowice on Friday, returning on Sunday, the flight is close to £200 before extras.