Several years ago I wrote this reddit post analyzing LEGO piece pricing: https://www.reddit.com/r/lego/comments/1328f52/detailed_lego...

It's a little out of date, but the conclusions are still relevant.

Main things of note: Brickheads are pretty economical as a "parts pack." No significant correlation between per-piece pricing and IP licensing (except for Star Wars). Star Wars and City sets are overpriced.