Developing full ideas that is going to make real difference in the market is a hard thing for most people. That's why collaboration usually helps a lot. If you don't have the money to buy collaboration and if you're fond of open source development, you may try to incite people to work with you in a project with an open license or even a not-so-open license (but that's gonna make hard to find prospective contributors). If you're happy and succeeds to get the right people, the found momentum can make your idea a great hit and opportunities will come for earning money in consulting, training, etc. As a starter of the project, you will certainly be qualified before customers to make the best with the tool/application you helped to create. On another setting, it is also possible that the project never consolidates into a concrete release or that the market simply doesn't care for it when it is ready. It is a cruel world out there, but some do pretty well. Sometimes the winners are lucky, or sufficiently hard working -- you will hardly find a definitive pattern for all the successful people and ideas.

On the other hand, you may hide your idea behind the curtains and work it out on your free time, struggling to get it into shape. That may work too. And can possibly fail as well.

IMHO, I think there is no silver bullet, but working on the many aspects of a great-selling idea. And that involves technical development, social skills to sell the "product", managerial skills to not bankrupt before it is finished, etc., etc.