I like the idea of quantifying garment quality but doing it in terms of price is a fool's errand. Better to make up an arbitrary scale that ranks garments from various makers on an absolute scale and then use the price to compute some kind of "value index."
Obviously it's highly subjective but the idea of some relative experts agreeing on a set of criteria and a scoring/weighting system isn't crazy. It's how lots of things are ranked. Universities, some sports rankings, etc.