Are there hidden costs to buying Dota 2?

I ask because I'm looking to get Dota 2, but I don't want to pay more than the upfront cost through micro-transactions in-game.

Is the game fully released yet? Is it possible to get for free?

The game is entirely free of cost to download and play. The only costs you'll pay (if you want to) are for content that does not even debatably give you an advantage in-game, such as cosmetic items, pennants to support your favorite team, or tickets to watch tournaments in-game.

You can get Dota2 here.

Dota 2 beta is currently free if you can get someone to give you a pass. You can buy a beta pass for $30 (in which case you get many cosmetics items). People in the beta are periodically given 5 passes to give to friends. The game is "F2P" and utilizes micro-in-game transactions. The store and pricing scale are very similar to Team Fortress 2.

The game is already released, and it is a F2P Game, meaning there is no need to spend money on the game (unless you plan on getting cosmetics or other items).

You won't have to pay a cent to play Dota 2 now!