The salary that is advertised with the job is not a very good representation of the money that you take home every month. At easyJet where I am crew, you will get money for each sector that you do, commission for products that you sell onboard. And if you stay at a hotel at the other end, you will get paid for the nights spent away from home. Your meals will be covered at the hotel too.
So although the basic salary is around £10000 pa, you will take home basic pay + sector pay + commission + night stop allowance which adds up to £1300-£1500 per month after tax, there will be a few months where you take home less for example when you are on annual leave. Through the summer months when your are worked off of your feet you will most likely take home more.
Other airlines may vary in their pay structure, some will pay slightly more, some will pay less.