Depending on the dvd, there may be only one for sale. Up in the Search bar enter the movie title. To the right, select DVDs & movies. Then from the left side of the page scroll down to where it says Location and pick North America. That is, unless you have an all-region and are shopping for imports, whereby you would choose Worldwide.
Once you've done that, whatever is available at the time will show up. If it's only one, well, better than none if it's a rare and out-of-print film you've been trying to find.