Install a shop into my existing WP site

I am looking for a wordpress developer to install a shop into my existing WP site/ theme (Contrast) www.doublezeroone.com

I need all shop & product pages created - ideally the existing product pages would become shop pages.

I am looking for what my options are regarding this - whether tying in a second theme would be easier / more affordable.

Please include options in your proposal as well as different costs for each.

Tx