I know how to make a Magento theme, but how do I set it all up to be sold on ThemeForest? What files do I include in the final .zip? And how can I host it if my hosting server does not support it?
You will need to put 2 folders with your files. One will have your templates and layouts folders(look in app/design/frontend/default/yourtheme), and second is with your css, js, images, etc. (skin/frontend/default/yourtheme)
About host, may be it is time to change your host