A lot of us have been here before. It wasn't clear but if you aren't you should set up a "feed" from something like searchtempest.com
It will send results based on your search parameters, "ford e350 diesel" click the "rss feed" or similar and it will walk you through setup.
Having the feed makes it so you are more likely to check the direct results everyday avoiding some of the regular search logistics, and irrelevant info. Be ready to jump on a good deal but also be mindful of the things you can't see.
Good luck.