It is always a tough job to earn some money from your own mind, working an eight hour or ten hour shift getting paid on that basis just doing what someone tells you with no freedom to exercise your own creativity does not seem worth it when you can earn more doing what you want to do using the ideas that you develop. Yes, working for a big company working hard day and night writing codes and php scripts and everything else just the way they see it is suppressing the talent inside you. It is not something that most of us would like to do, we would love to do something of our own this way, we love our work and we make more money out of it, but, it is not that easy knowing how to write a code or prepare good wordpress themes is not enough you should have the knowledge on how to sell it online and how to make something that is not just attractive but its applications have a good market value.
Things you need to do
First of all to sell your own wordpress theme or php scripts, you cannot just go posting advertisements or something, you need to find a platform that enables you to sell you product and at the same is trusted for keeping the product safe from piracy, you also need to check the authenticity of you product before going for sale, whether it has already been made or not. Then, you need to check into the website about its ratings and the value it offers to your product. The services they provide are charged, some of them might go for a high cut on your selling price but might be able to get your product a higher value on the other hand there may be some website which do not keep much of the commission but are not able to give you the selling price your product deserves.
When writing these scripts or making themes you need to keep track of latest trends prevailing in the market. This will help you analyze your options and the type you want to make. This also gives you a head start to work on your product. Keeping a track of the requirements of a buyer and testing the applications of your script will help in becoming a trusted author, once you create such an image it will help you get more money out of your talent.