Best language to use for shopping site

Tweet

I've been going back and forth with it and I'm not sure I want to go any further with my site at three pages now in HTML/CSS. I've been working on a shopping website and I would like to be able to change the top and side margins without having to manually update every page. I could use HTML with frames but I've never liked frames, they always seem to lead to trouble, and you have to have code in place in case the browser doesn't support frames. I've been thinking about doing it in PHP. What do you think?