Games : Is Hearthstone a pay2win game? [on hold]

I've found no distinct answer to this, so I thought I'd get an unprejudiced opionion here ...

After quitting Yu-Gi-Oh a couple of years ago since Konami became too greedy and it would've been to expensive for me to keep playing with all the new expensive game-winning cards, I want to start playing another competetive card game. Since I don't know any active players anymore that live in my viciniy, I prefer an online game over actual physical cards. Heartstone looks interesting, but I heard that you can buy cards with real money. I'm not willing to spend money on virtual cards, so my question is if I'll stand a chance against people who are. And I'm not talking about playing 3 hours a day for three months straight to obtain cards that I could buy instead, but rather if the game is balanced enough so that it is possible to win against "bought" decks without spending any money or a huge amount of time on the game.

Edit: More than one or two hours of playtime every other day or so would be too much for me.

Edit 2: Will this be enough for me to be able to play the game without constantly losing against people who spend money on it? If not, how much time would I need to spend grinding gold in order to be competitive without paying real money?