This seems like a perfect prayer to manifest more abundance. I don't know who wrote this, but I love it.
"Thank you for all the money I've been given throughout my life!"
If your knee-jerk reaction to that was to quickly note that you don't have enough money, money is in short supply, or anything related, take a moment to notice those thoughts and feelings. Put a white bubble around them, thank them and send them away. Then repeat this phrase (and the preceding step if need be) until you can think this and feel only positive and good vibrations around it. Think about only the good times, the times you had money, what you bought that made you laugh or smile, how you played with the money, and if you want dream of what you could buy in the future. Let go of any wayward thoughts, they aren't serving you and you aren't doing yourself any favors by focusing on them. And if it doesn't help you, and this is about you, then why hold your attention there?
I promise you that thinking and saying the words, "Thank you for all the money I've been given in my life," with a clear mind and heart will create a profound shift in what shows up in your life.