Virgo needs to understand everything, due to your Mercury ruler. If you can wrap your mind around all the details of something, you can usually learn to understand it as a whole.
This comes in super handy when it comes to handling the money you earn. While others are content to spend on big purchases, you're a little more practical by nature.
Reading the fine print on everything you sign, from a contract with your bank to any loans you take out, gives you a real advantage over other signs. You're patient with your cash, and this means you can enjoy it for a very long time.
P.S.: This is 100x more true during Mercury retrograde!