If you are searching Machinery Trader, I found a way to search that eventually landed me a good deal on a dozer (after missing several).
In the detailed search fields, input your criteria for make, model, price, year, or whatever filters you want to narrow the search to. Toward the end of the page, you can limit the search to ads placed within "XX" number days. Every morning, do the same search with a "1" in the number of days field. When a good deal pops up, get on the phone. Many of the advertisers on MT do not monitor their e-mails closely, so I would only e-mail as a secondary contact method.
Once a machine is located, it's just a matter of inspecting the machine and sending funds. I hope this helps. BTW, I'm in S. Texas, and prices "up north" are much cheaper than at home.