Expected costs for students work in Poland

I need student(s) work of about 100h/month. Work to be done at home, person(s) must have some computer/electronics knowledge.
No marketing or similar.
Needs own PC, mobile phone, internet connection.
Location in PL does not matter, although not too far from any airport would be an advantage.
Any idea, what I can expect as costs for 100h/month work ?

How long is a piece of string? Do you really expect a useful answer to your vague, ambiguous and even evasive question?