Tax on online income in Poland

I'm currently studying and living in Poland as a Polish citizen. I came across a legitimate idea to make 7x EUR10,000 online over a few months (depending on demand from my product). The money will be transferred to my Polish bank account.

Does anyone know if I will have to pay income tax on this? If so, how would I go about doing it in an efficient manner? I don't want to start a business as this income will only come in a maximum of seven times. Should I just wait until I have the money, then go and file an income claim? Or what?

Thanks in advance for any advice.

I'm pretty sure you'll have to pay tax on it in Poland if you're tax resident in Poland, and from what I know you need to make a monthly declaration, but you should really go talk to an accountant.

A monthly declaration is a problem because I have no idea how often I'll get paid. Is there some sort of end-of-year declaration I could do?

I hope there's an accountant here because I don't know any who speak English :P

where are you?