There are already more than one or two copies of Destiny out there in the wild but if you've been waiting until you can get a taste of the action (presuming you missed that massive Beta) now's your chance.
Activision and Bungie have confirmed that a trial version of Destiny is available right now on PS4, PS3, Xbox One and Xbox 360. All you have to do is go to PSN or Xbox Live and grab the download - the size is 20 gigs for new gen and around 6 for old gen.
Then just get playing. The trail contains a bunch of single player missions in the Old Russia area as well as a smattering of multiplayer elements and progress up to level 7. If you do decide to get the full game after this offering, you can instantly upgrade, with no further downloading needed.
That's a very nice deal (provided you're interested) but remember that your character progress can only continue on the same console. And there are also a couple of older Xbox 360 and PS3 models which the game won't work on, due to hard drive limitations - the details are here.
The Destiny Trail is live now on the above mentioned consoles. It closes off in January 2015 on Xbox 360 and PS3 and there's no set finish time on new gen consoles yet.