I had to read this to understand the question properly.

Hermione decides the best way to choose is by determining the minimum number of gold galleons needed to buy each non-evil wand of high power and age.

Is poorly worded as they are looking to find a wand with the cheapest price for the given properties.

Unless each wand with the same properties is considered the same wand - but then why would they have their own ids. blah.