What should I charge for installing a shopping cart?

[brodiek]

OK, so basically I'm an experienced web developer with years of experience writing advanced PHP scripts but I've never installed a shopping cart like os-commerce before.

How long should something like that generally take to do? Keeping in mind it's not just an install but a complete customization to look like a part of the origional site.

Anyone have any ideas on how much time it'll take and what I should charge for something like this?

Thanks.

[ShrineDesigns]

if you got a testing server on your home computer, do a test install on your computer

charge a fair price, perhaps they'll come back to you for more jobs

[MarkL]

However much you want to charge an hour is up to you, the standard in my area is about $50 USD an hour.

How long it will take is a different story, and there are a lot of factors that are going to be involved in that.

I have found that no matter how long I think it is going to take to write a certain script, the actual time I spend on it is about twice as long, unless I take this into account and quote the larger amount, in which case it seems to take about half as long as I had anticipated. I will call this "MarkL's Paradox", which can be described using formal logic, as is shown below:

P1: A PHP script (x) takes time (t) to complete
P2: If (t) is proposed by the actor (a), then (x) will take (t)*2
P3: If P2 is taken into account by (a), then (x) will take (t)/2
P4: P3 and P4 do not make sense
C: You must acquit