Re-writing site required to add Shopping Cart ?

[sliding]

My site is up ( ShelfThatGlides.com (http://www.shelfthatglides.com) ) but with no shopping cart. I am sending customers to my first site ( SlidingShelf.com (http://www.SlidingShelf.com) ) to complete their purchase.

It would be much better if there is a Shopping Cart at the new site, but from what I've seen I would have to re-make the site . Is that correct, or is it simply a matter of adding a Shopping Cart to whats already there ?

[stevel]

It depends on which cart software you choose. Some, such as osCommerce and Zen Cart. are self-contained sites or subsites that can be customized. Others, such as the PayPal Shopping Cart and Americart, allow you to add cart features to existing sites.

A lot depends on how much work you want to invest.