It has three expansions bundled with it. I've never played, but it's my understanding that these three expansions represent the initial must-buy content.
Ah of course. However I read recently that someone had the base gane and extra products but Bungie decided it wasn't making enough money so removed the base game and has gone a different route. Removing the players items and game data.
So I'd highly recommend nobody touch destiny with a barge pole. Bad consumer practice. Would prefer if they disappear from the gaming industry