Hi,
I saw the Nike site... budget about $25,000 - $30,000 for a site like that with those kind of features. Minimum. And a lot of interaction with the web designer who has to design those features.
60 - 90 days with a team of 3 - 4 people.
A simpler website would still be in the $2,500 - 5,000 region if you need all the colours. You will also need a dedicated server if your traffic volumes are high. About 45 days.
It would all depend upon the number of jeans, the designs, colours etc that you plan to offer. In both cases, you will have to lay out the specs clearly or you are heading for a flop.
Regards,
Gurjar