Commercial PHP Scripts
Often, commercial PHP scripts can be purchased to fulfill required functionality on a website. The can be stand alone scripts which work by themselves, or they can be extensions, addons or plugins for other free or commercial PHP scripts / software such as Joomla, WordPress and Magento. Surfing the Internet and browsing PHP web directories will allow you find the desired script. Whether you want to run an auction, ecommerce store, social network, forum or live web feed; you will find many options to choose from. Since php is the most popular server side language on the Internet by quite soime margin, it is very likely that you will find what you need coded with this very popular programming language.
Advantages of Commercial PHP Scripts
Most of the time, commercial PHP scripts are well made, have many options, and have decent support. On the other hand, free php scripts tend not be as well built and have as good support as commercial scripts; although that is not true in all cases.
Stand Alone Commercial PHP Scripts
Some examples of stand alone PHP scripts of the commercial variety are; V-Bulletin, PHP Auction, Magento Enterprise Edition, Sugar CRM Professional and the list goes on. Stand alone PHP scripts are often coded well so that they run very fast, and / or they have a lot of power to run a sophisticated website.
Addon Commercial PHP Scripts
Some examples of commercial addon php scripts for Joomla are; Joomla SEO, sh404sef, various Virtuemart extensions and Jomsocial. Often, commercial extensions have a free version or a trial period while others do not. When the potential client experiments with the free version, they would get an idea if they would like the better, fully featured commercial version.
Free PHP Scripts
Often, simple php scripts like calculators, file uploaders and rss feed aggregators are freely available on a large scale since they are built rather quickly and are very unlikely to be sophisticated enough for a programmer to charge for them.