This normally wouldn't be that huge a deal, but given how Lemonade first dropped as a Tidal exclusive—meaning it was only available to listeners on the streaming service, which is largely owned by her husband Jay Z, though Bey has a partial stake—this is a speedy development, seeing as we're not even at the 48-hour mark of the record's release.
Like Kanye West did with The Life of Pablo, Beyoncé opted to give Tidal users a leg-up on the new material before bringing it to another retailer. In Kanye's case, TLOP was available for purchase via Tidal and his own website; with Beyoncé, Lemonade remains an exclusive Tidal property—in some respects. Lemonade is now for sale on iTunes, and physical copies of the album will be available as well; Tidal said that it would hold onto Lemonade "in perpetuity" when it comes to streaming, though, which means that the album won't be an option for Spotify and Apple Music users.
To sum things up: Yes, you can buy Lemonade. No, you don't have to subscribe to Tidal to get it, but you do have to have Tidal to stream it. Got it? Good. Now go throw "Sorry" on repeat and brace yourself for one beautiful and intense listening experience.