Will more expensive skates help her skate better?

Not necessarily. You want a skate that is appropriate to your skater's ability. A skate that is designed for a very capable skater will be stiffer to support the ankle when landing jumps but that stiffness will make it hard for a skater who isn't at that level yet. So, in some cases, a better skate will give your skater worse performance. However, once they get to a higher performance level, you can expect to be spending more on skates to get better performance. The top skaters buy their boots and blades separately.