Render Price Breakdown question

[sampakinpa]

Hi to all,
I'm doing a price breakdown for a client that include a big quantity for modeling and rendering in Octane Render engine.
I have no problem to figure out the time/price for modeling and preparation to render. but I don't have a clue about the actual rendering time pricing breakdown.
I'll appreciate allot if somebody have an estimation of the price per hour I need to give for the actual computer render time.
Thanks.
Ethan