To describe an immature girl who is always on the lookout for a rich guy to marry in order to enjoy instant benefits of wealth.
Typically, it is used to describe young girls who hook up to rich guys much older than they are using their bodies in a subtle manner, similar to girls who are looking for sugar daddies.
Girls described this way tend to be pretty, smart and manipulative in their ways as well to get rich guys to drool over them and shower lots of greenbacks over them.
It's obvious she's a shoezgal, hooking up to the richest guy in town of 30 years old when she's only 17. How else would her family be able to fund her spending ways?