Let me first start out by saying this: I am not affiliated with Themeforest in any way shape or form. I am simply a very satisfied user and felt like I should give them a shout out.
Themeforest is part of the Envato Marketplace; a market place which features everything from audio files to stock graphic images. I won't go into too much more detail about it though, because this post is about Themeforest.
There are numerous reasons why you should visit, use and contribute to Themeforest. One, the themes are exclusive. You will not find the themes you find on their website anywhere else on the web. Its an exclusivity thing that designers and non-developers like myself can really appreciate. They offer everything from frameworks to templates for HTML, WordPress, Joomla, E-mail and more. And the best part is: everything is fairly priced.
I have used a few (what I call) theme/frameworks from there. These are themes that are so customizable that they are basically frameworks that are so well developed that you can seemingly create child themes without any trouble or an extensive knowledge of HTML, CSS, PHP and all that other fancy stuff. The customer service has been impecable. And while I understand that this is not themeforest staff providing this service, it goes to show what kind of users and developers are found on this website. I have not found one yet that I have not been impressed with.
They even have an affiliate feature built in. So, while I'm not interested in being an affiliate (at this point, anyway) it seems it is a fair affiliate system for anyone willing to promote themes they like, or even just themeforest in general. You know, to hopefully make a few bucks.
They have a very handy checkout feature, too. You can make a deposit of a certain amount of money which you can use at any time to purchase a theme, template or framework. OR you can simply pay with paypal for $2 more. Your downloads are then stored in your profile so that you can download the file(s) again if you need them without paying again. Very handy.
Overall I really recommend you check this site out. It is a website that will be very handy for everyone, even if you know nothing about web development or know everything.