There are 3 reasons why some girls seem materialistic, there may be more but this is what I've come up with;

1) To keep up appearances- you will find that girls who need to wear the latest fashion or have the fanciest mobile phone feel the need to impress other people. Unfortunately many girls fall into this trap.They succumb to the pressures of society and find that it is easier playing the cool girl than fighting taunts for being an individual.

2) Security- when you come across a girl who wants to know how much money you make, it's generally because she is ready for a relationship and wants to know whether you are able to give her what she needs. She may not be materialistic, it's just that she's probably been in a relationship with a loser who doesn't pay his way.

3) She's a high achiever and/or a provider-There are those who's main focus is making money and may tell you how many cars and houses she has purchased. If she is a high achiever she is just wanting recognition for her hard work and is probably sizing you up for a relationship. If she is a provider (many under this category may be both) then it's because she wants to provide financial security for her loved ones.

It is important not to judge those who seem materialistic at first because we all fall into the trap where we want to appear different to what we really are.