They'll come in packs of two, including both a right and left controller, for $US60 (local pricing not available at the time of writing).
The link contains a FAQ page and a full table of the features available to Nintendo Switch online subscribers over those who do not subscribe, which you can see below. We might hear about more games during the Nintendo Direct on Thursday.
In terms of perks, you don't get current gen games for free like you do on PSN.
Mauricio Pochettino Backs Hugo Lloris Following Drink Driving Admission
Tottenham goalkeeper Hugo Lloris hasn't ruled out a return to action against Liverpool FC in the Premier League on Saturday. The staff, the club, the fans, us, and he said "Any decision that you take gaffer, or the club, I think is fair".
UPDATE: Nintendo's online page has confirmed the first 20 games for the NES: Soccer, Super Mario Bros., The Legend of Zelda, Ghosts 'n Goblins, Excitebike, Tennis, Balloon Fight, Super Mario Bros. These controllers are modeled after the original NES ones and can be attached to the Nintendo Switch console to be recharged just like the joycons.
Nintendo recently announced that its online subscription service will be going live in the United States on September 18 and a day later in Europe. "It will also be possible to play these games offline". I'm not actually excited for Switch Online at all so far, but I also don't play any video games online. So...