templates with php

Hi there! I'm starting a new project from scratch and I my idea is do it with html templates. What I mean is a directory with some templates like index.html, details.html, checkout.html, etc, which one with symbols in it, like @title@, @price@, @description@, etc... When the page is requested some kind of pre-processor reads variables and show the dynamic page. My question is how can I do that with php? What's the best way? Regards Carlos