Until you learn the ins and outs of dynamic e-commerce websites, you could try a content management system (CMS) such as Joomla (http://www.joomla.com). This will not only allow you to easily customise your site but there are a huge number of simple add-ons that integrate very nicely. You can get shopping cats, payment gateways, hotel booking engines etc. etc. It's also Open Source and free.