What is the ZUS rate?

Can anyone tell me what the ZUS rate is? Or what it is based on? I know what the tax rates are but this ZUS thing is not as clear cut.
Also, a self emplyed person, do they have to make a return monthly or can they not do it quarterly?
Thanks.

For self employed/company owners It's something like 750 PLN a month (something like 200-300 for first 2 or 3 years, but I think It's only for young people). It's going to be lower, but not much.



Monthly I think.

Thanks for the info. Had gotten that amounts alright. Just thought it was quite expensive but that is apparently the way it is......And from what I hear, the goverment have given ZUS money to the church