YES!

Basic site design integration is included with the purchase of a Site Store Professional PayPal, Enterprise or Developer License and even for trial users!

Site Store Professional will apply our shopping cart to your existing website design for NO CHARGE!  Site Store Pro can be applied to ANY website design in approximately 10 minutes and all we need is FTP access to your hosting account or a HTML mockup of your site design and we can integrate the shopping cart into your specific site design.

If you want to do the integration yourseld, Site Store Pro support will assist you with integrating your existing website into the shopping cart system by answering general questions regarding layout, CSS file modifications(s) and which content is controlled through the web-based admin versus the actual page design. 

For additional information on design integration, please visit; http://www.sitestorepro.com/help/#Design_Integration_Overview.htm