The best craigslist tool I've ever used is IFTTT (
https://ifttt.com/connect/craigslist/gmail) . Say you want to see all "van" posted under "$1500" in "vehicles-by owner" in a specific area, you can set up a script to send you an email as soon as new stuff for that search gets posted. If you have notifications for emails set up on your smartphone you'll likely be the first to know about the posting and can be right on top of it. That's just one example. You can also set up general ones so every time someone posts something under "free", for example, it will send you an email right away (this might crowd your inbox though). You could add a location to a query (e.g. california, west, denver) in rideshares and get emailed as soon as someone posts something involving that, or "backpack" in sporting goods, etc. Basically your imagination is the limit. It does take a bit of tinkering, but I think it works pretty well.