Free, simple to use and easy to modify shopping cart script. Minimal requirements: PHP 5.2 +, 2 MB disk space and 5 free minutes to install! Doesn't need MySQL or any changes in Apache. Users value it for its great Google results, its very good performance, compliance with many standards (HTML 5, WAI and CSS) and its technical support. Its other important qualities are: easy modification of HTML and PHP, jQuery, WYSIWYG editor, no unnecessary options, mobile version and most importantly it's still evolving for over 10 years.