Doing a website for someone, how much to charge?

I have a guy that wants me to build him a shopping cart website.

I plan on doing it with wp and an WP shopping plugin.

Now he says that his budget is between 3-4 k . I work with the guy, he is actually one of my managers. He will also need me to promote his site to get traffic.

I will need to create his logo, and add all of his products to the site, and setup the rest of the payment and shipping info for the products.

I am also planning on signing up for a reseller account and charging him around 15-20 bucks a month for hosting.

So what do you think I should charge for the site?

And what would be the a fair amount to charge him to promote it?

I was thinking of using something like senuke to build towards bringing traffic, and if he wants instant traffic, I can get him to pay for adwords.

I am really not the king of traffic, so any other suggestions would be appreciated.

I want to give him a deal, but I don't want to spend all my time promoting this for him for peanuts.

Thanks

if you want to just do it and be done with it, charge him about $2500, plus a monthly to manage it: something like $30/mo to host and update.
if you think its something that will do well, take a percentage of the profits and do it for free+hosting. that way its really in your best interest to manage it and keep it up

Thanks for the reply.

I was thinking that exact amount.

I was going to include the first year of hosting with that.

Also thinking of charging 150.00 /month for promoting and any updates or questions.

Do you think my approach to getting him some traffic is a solid plan?