Amazon Prime's list of benefits grew one bigger on Thursday, as the $99/year subscription service now includes free same-day shipping—and same-day delivery—for certain parts of the United States.

Should an Amazon Prime member live in one of 14 qualifying metropolitan areas—including the company's home base of Seattle, along with the Bay area, New York City, Washington, DC, Atlanta, Baltimore, and Boston—they can get free same-day delivery on orders of $35 and up. Be advised: you'll want to check at Amazon's zip code search site for your own eligibility if you live in a sprawling region; our test of addresses in the Seattle and Dallas/Fort Worth regions proved scattershot.

Qualifying same-day orders that cost less than $35 will be charged an additional $5.99 for same-day speed, as Prime customers had already paid up until today. Meanwhile, should an order be placed too late in the day, Prime customers will still enjoy free one-day shipping.

The site's search filters now include a "Prime same-day filter," which is distinct from the standard Prime-qualifying two-day filter. The news announcement didn't clarify how many of Amazon's button-affiliated products will qualify for Prime's free same-day shipping, but we wouldn't be shocked if Amazon was working on a system whereby its buttons will someday make bottles of Tide magically materialize on top of your dryer.

Note: This post has been updated to clarify that the service offers same-day delivery, as opposed to same-day shipping.