Most, if not all European LCCs have always sold food - and what's more, it's an extra source of income, not cost (because the food & beverage is so damned expensive....)
Europe's two largest & most profitable airlines do this (FR & EZY).
Selling such items is not considered "extra work", but simply part of the FA
's normal course of duties.
As for pay, I'll allow you to make your minds up:
Don't know whether you'd consider that well-paid or not; in Britain, it is generally acknowledged that cabin crew/FAs get paid very little anyway, whatever the airline. You certainly don't do this for the money!