So, I hope I'm understanding your question correctly: You only want to know how to physically travel from Poland to Czechia with no money, right? (You're not asking about what work you could do in Poland, etc, I think?)
I'm assuming you don't live close to the border, otherwise you wouldn't ask?
The obvious, walking yourself there, or bicycle - probably not in winter.
Hitchhiking - do NOT hitchhike, being a girl. Don't trust anyone.
What if you could online apply for actual jobs in Poland? They might offer to pay for your travel cost to get there.
Is seasonal work still a thing? Used to be that people would be moved to another country for a few months at a time to do work there. That would be more in the summer time, I think, though, picking fruit etc.
Again, though, even with this - be extremely, extremely careful, especially as a female. Always trust your instinct. Always make sure you're safe. If someone says you're being too scared and you're exaggerating, don't listen to them. Trust me.
You could apply to work as an au pair, if you like children?
Or maybe there are really, really cheap buses going through Europe (have you looked at Flixbus)?
That's all I can think of right now, but I hope you can get something figured out soon
