But with Wizz Air you can avoid card fee althogether by depositing 300 eur or more to your Wizz Account (you then have to spend that in one year).
300 Euro? You are kidding? I wouldn't really call that avoiding the charge, seeing as you have to pay them 300 euro upfront, which I would not consider doing no matter who the airline is, and the majority of people who would use low cost airlines generally would balk at that.
I don't use Wizz so much these days, I used to use them quite a bit, but charging for standard size cabin luggage just to take a bag to last me long enough for a trip costs me 10 euro extra than Ryanair before you even take into account the fares. I used to use Wizz a lot more but some of the changes they've made in the last year have put me off.
Ryanair also tends to be a little cheaper for most fares, as they don't restrict them to people who have paid a membership fee like Wizz who want 30 euro for their discount club and frequently make low fares only possible to be purchased by such members and Ryanair tends to be more punctual and better in times of disruption.