I will start this by saying that there is no cap, no limit, and no boundaries in which we are capable of. Now I know a lot may disagree with what I have said and to them all I ask is read on.
Ok so let me explain for the beginners reading this trying to cast a spell for more money than he/she needs or is just plainly not getting the desired result of abundance in their life. Before you begin any magical practice you must begin to know yourself and you inner most true desires. For example, not everyone wants a lamborgini or bugati. If you dont have a car at all then you want transportation or the stability of having your own ride or maybe just the achievement. My point is what will make you happy. I mean what would really just put a smile on your face, not make you all out jump for joy (although this works better the happier you are when you receive the small things).
Think of it like this;
Right now lets say your on level 1
As human beings we seek growth everyday whether it be in wealth knowledge or spiritual. As a Mage (magician, wizard, witch, or whatever name you claim) we utilized the ability to manipulate energy to help us with this. Now if you are just beginning this will most likely be difficult since you are not completely sure of your gift yet. So I would recommend only reaching for level 2, that smile :). If you want millions start with a dollar. If you want complete happiness start with being happy with what you have now.
Now lets say you've reached level 2
Again as humans we need growth. You have a dollar now and your happy with what you have but it doesnt feel like enough anymore. As soon as you feel this it is time to move on and you must act fast. The longer you wait the more your happiness will fade. So since know you have the ability to go up one level, since its our natural instinct to grow, you will want to go up more than 1 level you can try 2 or maybe that one level up has increased your faith in your ability so much you can go up 5 levels closer to your goal. And with this your only limits are the ones you set for yourself.
I hope this helps and be sure not to bite off more than you can chew (greed) because the acknowledgement of failure hurts this process majorly.