Travel / My First Visit To Poland, Warsaw. Invited There As Part Of Photography Programme. [5]

This is my first visit to a foreign country. I participated in a photography competition called 3rd VISTULA ART AND DESIGN COMPETITION in Warsaw, Poland.

And won the merit prize, As part of prize they have called me to Warsaw and attend art workshop for 6 days near Mazury Lake.
I tried to call the contact mentioned there, But they aren't really responsive and all they say is " its all given on website".

I am really confused whether to go there and attend and spend that amount of money on airfare, travel and lodging.
I really wanted to know places, where i can stay in Warsaw or places nearby,in considerably cheaper accommodations.
Any suggestions on how i should travel safely within the city and country, How do people react to foreigners there?
Good places to photograph culture of Poland, People and their way of living, Safest remote places to photograph landscapes and remote culture there?

I just have 300$ budget apart from my airfare. I can extend it, but I'll have to ask my father. Which i don't want to do. As he is already doing so much, We being a middle class family and all.

I want to do this on my own.
I am posting the link below to the Workshop and Programme

i.vistula.edu.pl/moodlwp/international-art-workshop/

Any help would be appreciated
Thanks :)