Life / Migration To Poland - cost of living, work, safe for a girl? [20]

Hi I am Angeline From Sri Lanka A county in south Asia ,and i am Girl of 21 years,
I Have a Idea to Go Abroad and Live in a Europe Country for 1-2 years ,
I have some Interest on Poland also ,

Can I know. How much it is Cost for living for A Normal (Not a Luxury life) life in Poland for a Month ,
and is that easy or hard to find some job from Poland for Non citizen people ? , from any supermarket or any place that can be suit for me,and can cover Monthly expenses

and is that want any work permit to work . and What are the best cities with law cost of living , and with safe for a girl .

Thanks