How do normally vector-illustrator freelance artists (not digital painting) charge their clients?

Someone informed me that some vector-illustrator artists would charge their clients based on the complexity of the scene or sometimes number of lines drawn. Is this usual???


for an example; a simple scene with 100+ vector lines lines drawn would cost approx. AUD 200!!


Then again, I know someone who earns approx AUD 200 for 5 days worth of illustrations (1 project) with complex scenes. I'm thinking to get into freelance myself but do not know what's the standard of setting up price.How do normally vector-illustrator freelance artists (not digital painting) charge their clients?
A friend of mine claims her husband (who does this kind of stuff) basically bids on the job. He can tell approxiamately how much work and time it will entail and quotes a price that he believes will cover his time and expertise. Of course he's fairly experienced so he knows how much work is involved.