Designer or Developer

I want to purchase the 68 Classifieds script but I am unsure as to whether I should get the Designer version or the Developer version. I will be wanting to customize the templates and possibly incorporating some of the add-ons available, however I currently have no knowledge of PHP programming.
Can somebody give me some advice. Thanks

[seymourjames +]

If all you wish to do is change the look and feel of the template then the designer version suffices. However, if you wish to change functionality and retain complete flexibility then the developer version is for you. In general, many people who start with designer after they become more knowledgeable and their functionality requirements change do upgrade to developer.