Ok, recently my Dad called me to tell me he knew a guy that needed a business web site to sell his product. I need help on prising, I dont want to rip the guy off, since he isnt rich or anything... of course I dont want to be ripped of either, I would maintain the website, set it up, and do everything else.

I thought that 300 american dollars + 4% of sales(not profit) would be fair. what do you guys think?

oh, and the website needs automated buying, I dont know how to set this up, but the rest(customer database, Java,html,etc) would be easy for me. can anyone point me in the right direction.