going rate

Hi all,

 I`ve been scripting for a while within my company, but recently I have been approached to write a script as a freelance job. Thing is I am a bit in the dark as to what would be suitable price to charge. I know that this would depend on the complexity of the problem and how long it would take me.

here is some info:

its  a scene optimizer, so it should clean out materials  not assigned to anything delete objects with no faces.just niggley little things. I`m thinking it would take me a couple of evenings after work so possibly 6 hours ish? Also I`m thinking about how much time it will save the client, so I was thinking a rough figure of about £450. Does that sound wildly over the top or totally undervalued?

Anyway any thoughts would be welcome

Cheers