If you waited until now to buy a smart speaker from Google, Amazon or Apple as a Christmas present, the pickings are going to be slim. Apple's $99 HomePod Mini, introduced in November as Apple's first consumer priced smart speaker, is sold out and not available until Jan. 4, according to Apple's website. Google's Nest Audio, the redesigned version of what had been called the Google Home, is also sold out, and not available until Jan. 8 at the earliest, with free delivery from Google's website, or Jan. 6 if consumers pay an extra $22.99 to expedite the order. Amazon's Echo Dot, the smallest and least expensive of its smart speaker lineup, has long been one of Amazon's holiday best sellers, ranking as its most purchased item last Christmas. This year there's a redesigned Dot with a built-in clock, but it's already sold out for the holidays.