Craigslist is the hub for local transactions and knowing about posts that have been made can allow you to get a step ahead of your competition. I found a great suite of apps for your Android device that will give you notifications each time something that is relevant to what you need is posted. To set it up you will simply create a search criteria that you will create a scheduled search for. These searches can be set to be done as frequently as every 10 minutes. When a new item that is posted under your search criteria, you will receive a notification.
This set up requires two peices of software for your Android Device: