Amazon Studios thinks it has produced some amazing original series — and now it’s launched a new promo to try to get more people hooked on them and sign up for its Prime subscription plans.

The e-commerce giant is making 10 Amazon original series pilot episodes available for free on the Amazon Video YouTube channel and Facebook page, including the season 1 premiere of celebrated transgender dramedy “Transparent” starring Jeffrey Tambor.

Each of the pilots has already been free for anyone to watch on Amazon.com. So the new sampling strategy — coming in some cases more than two years after the shows originally debuted — is a sign Amazon has concluded that compared with its own website and apps, Facebook and YouTube are better suited for building buzz and encouraging viewers to share and comment on the shows. It’s better late than never, perhaps, but the move raises the question of why Amazon didn’t come out of the gate with a broad sampling strategy.

In addition to “Transparent,” Amazon original series pilots now streaming on YouTube and Facebook are dramas “Bosch” and “The Man in the High Castle,” comedies “Mozart in the Jungle” and “Red Oaks,” and kids’ series “Annedroids,” “Gortimer Gibbons Life on Normal Street,” “Just Add Magic,” “Tumble Leaf “and “Wishenpoof!”

To watch the full series, users must sign up for Amazon Prime at $99 per year, which includes free shipping on millions of products, unlimited access to Prime Video and other perks, or the standalone Prime Video plan for $8.99 per month.

Continuing to battle category leader Netflix, Amazon expects to double spending on video content in the second half of 2016 versus the same period in 2015, as it nearly triples the number of Amazon original TV shows and movies, CFO Brian Olsavsky said on the company’s Q2 earnings call. Amazon previously said it spent $1.3 billion on Prime Video content in 2014.

Amazon original series scheduled to premiere this fall include new seasons of “Transparent,” “Mozart in the Jungle,” the second season of “The Man in the High Castle,” and new shows “Good Girls Revolt,” “Goliath” and “Crisis in Six Scenes,” Woody Allen’s first TV series, as well as “The Grand Tour,” the new series from former “Top Gear” hosts Jeremy Clarkson, Richard Hammond and James May.