There are a number of useful Craigslist search agents, apps, and tools. I will share my favorites.
1. Craigsnotifica–Droid Ap that I use to keep tabs on what’s being posted throughout the day. I have particular searches saved that notify me whenever certain terms come up. For example, I know a lot about vintage Gibson guitars, so I have a saved search called “vintage gibson”
2. Search Tempest Website tool that allows you to search all of Craigslist at once; allows you to search within a designated geographical radius, i.e. 250 miles. I use it regularly. Especially useful for finding rare items.