Guys, a few facts - from somebody living in Poland, working in Wizz, and familiar with self-employement regulations in Poland (although nobody seems to listen):
1. Bond in Wizz depends on your rank when you join - cadets get 4 years, 20k bond with 10k returned after it expires, experienced FO's get 3 years, 15k and 7,5k back after 36 months etc. Don't remember the details for skippers.
2. As I wrote before, this self-employment (setting your own company, providing invoices for flying, getting only 19% tax) is NOT legal in Poland, despite many people doing it (not only in aviation). Some time ago, the Polish Labour Inspectorate did an audit of LOT Crew and their bogus self-employment, the conclusion was simple - crews should be employed, not contractors, as they meet all the evidence of being employed by LOT (they only work for one airline, they cannot work for anybody else, they don't decide when, where and how they work - LOT does, they use LOT equipment etc.). But it continues, because the inspectorate lacks any means to enforce it. However, just last week there were news of the Polish government working on a solution to that, to be able to effectively challenge this bogus self-employment (because they lose a lot of tax money that way ofc).
At the moment there is no RYR in Poland - there is Ryanair Sun (soon to be renamed Buzz), which is a separate entity, separate AOC, separate work conditions from mainline RYR - and they use similiar setup as LOT (look up Warsaw Aviation agency).
3. Somebody mentioned sick leave - when you are employed in Poland, you don't just get basic pay then, you get 80% of your AVERAGE salary (including extras like sector pay, office duties, bonuses etc.) from last 3 months