Local shopping search tool Milo.com has expanded its coverage of 50,000 retailers to allow customers to watch for local sales. Milo already offers what the company says is “real-time availability and pricing information.”

Why use Milo? Because your local big-box retailer often doesn’t have the exact same items in stock as the company’s website. For instance, Milo.com can list exactly which televisions are in stock at the Best Buy in Bangor, Maine. It’ll also tip you off that the store in Portland, a couple of hours away, has a model you might want instead.

“More than fifty percent of retail is done at big box stores,” Milo.com CEO Jack Abraham told me in a phone interview. “Outside of San Francisco and New York, a shopping trip for most people involves driving one way or the other. We can save people a lot of time, by telling them what’s in stock at their local outlets.”

Milo works better for non-clothing items like cameras, barbecue grills and TVs. When I tested it by looking for boots, I got a lot of out-of-stock notices, and not that many boots all told. Abraham says that’s because clothing retailers don’t track individual items as closely as sellers of less personalized items. Clothes come in different sizes, colors, cuts and patterns, so it’s harder for retailers to maintain a database of boots than a database of cameras.

Still, Milo’s massive database of two million-plus products makes it worth hitting before you get in the car.

Milo.com, founded in 2008, is based in Palo Alto, California. The company received a $4 million round of funding from True Ventures in November 2009.