Sketch - 7 zł/ 2 €/ 3 $
_{additional character - 3,50zł/1€/1,50$}

Lineart - 10 zł/ 3 €/ 4,50 $
_{additional character - 5zł/1,50€/2,25$}

Digitally coloured sketch/lineart - 15 zł/ 4 €/ 6 $
_{additional character - 7,50zł/2€/3$}

after I show you the sketch and you like it and everything's ok [in this case I show you the art right after I finish the colouring]
after I tell you that I've finished the art [in this case I show you the finished version only AFTER I get the money.]

Porn - NO.
Yaoi/yuri - yes, but NO sex, no difficult positions etc. Just some hugging, cuddling, kiss on the nose or on the cheek, maybe some slightly suggestive situations.
And only characters who originally are gay [no sick fan fantasies please.]
_{[and personally I prefer yuri to yaoi, so you know.. xD]}
Slash - Urgh... I'd REALLY prefer not to... But if I say yes, then... nothing more slashy than this [link] . And it also depends on the fandom.
Pairings I don't like - Probably no, but that depends on how you would like me to draw it. If you have an interesting idea I may agree.
Characters I don't like - The same as above.
Characters I don't know - Well, yes... but you'll have to give me some information and references on the character so it would be easier for me to draw them.
Your OC's - Yes please but of course references and information are needed.
Animals - well, I don't draw them too often so I don't know if I'm good at it, but I may try
Robots, machines, etc - as long as nothing complicated, yes.
Ideologically controversial things - depends on HOW controversial it is..