It's easier to manifest the twenty dollars if you really let yourself believe it is possible. Also, taking action steps is another important consideration. A year ago, I was not working, trying to make a go of it is an author. Money was tight. I started taking action steps to improve our finances, and the universe met me half-way. Yes, I did have to go back to work, but the universe presented me with options that paid well and took very little time on a part-time basis, so I could still continue my writing on the side.
If I hadn't been using the Secret guidelines, my reality might be different, with a straight nine-to-five that doesn't fulfill me and no more time for my writing endeavours. You'll find a balance point between belief, action steps, and reality.