Valve today announced through a press release that the upcoming DOTA 2 will be a free-to-play title, and in preparation for the DOTA 2's release, also announced the DOTA Store. When the DOTA 2 Store's doors open, it will offer items created by Valve, and members of the community.

These items can be used immediately, and will be carrier over after the public launch of DOTA 2. Early access to the game isn't required in order to purchase items before the launch. Gamers may, however, get into the game now by purchasing the DOTA 2 Early Access Bundle of items. IceFrog, design lead on DOTA 2 says:
The opening of the Dota Store is a big part of our final push to launch. With support for the Steam Workshop, the majority of the items made available on day one were created and being sold by members of the community. By making the game Free to Play, we hope to give gamers the ability to decide how - and how much - they want to invest in the game.
DOTA 2 is slated for release on the PC later this year, and promises to deliver a "unique blend of online RTS and RPG action that has made Dota popular with tens of millions of gamers around the world".