A Chrome and Firefox browser extension that enhances the Steam storefront with all kinds of extra information including price comparisons to other online retailers and the games historically lowest price.
As of July 2018, the extension has been discontinued. See http://www.enhancedsteam.com/blog/?p=256
Provides many utilities for steam inventory and market (offers notification, quick selling, buying, offering trades, price check...).Warning
The extension requests dangerous permissions and it's reportedly monitoring and sending your online activity to their own server, for promotional stuff it seems: https://www.reddit.com/r/GlobalOffensive/comments/70xofs/warning_trusted_steam_inventory_helper_now/