How can i refund a game on steam?

you need to get a steam premium account for that

All you have to do is believe in yourself!

Contact support. They may or may not do a refund.

Can't get a refund but you could trade it for other games or TF2 keys, which is basically steam wallet anyways

Steam doesn't allow returns, BUT you can trade it on the Steam Trades forum for something else since its a gift.

+1 for steamtrades. BUT if it's not urgent, wait a few weeks with it. On sale's last day probably all the discounts will return, making Torchlight 2 worth only the sale-price. If you wait a few weeks/months, it will worth it's full price.

Steam has a shameful return policy and overal customer suport, as a general rule they usually give the first refund or take a game from your library but only once according to them, it's ridiculous but that's how they do it, so if it's your first time I sugest you don't contact suport since it's a cheap game.

Well, if you REALLY need that money back, you can write to Steam Support to ask for refund.

Just ask nicely, focus on reason why you want to return it. They will probably write something about one-time thing, but you should get your money back.

You won't be able to get a refund most likely. You can only hope to trade it or give it away. By the way, next time, ask your friends before you gift them something.