The other thing I want to mention is that running shoes are a lot like basketball shoes in that companies release models yearly. However, they often don't change the foundation of the shoe much (at least Brooks and Asics didn't) so you can then get last years model deeply discounted.

Good reps at running shops can give you the 411 here, too. When my kid was running HS cross country/track this saved us a ton as he was going through multiple pair during training and season.