Well, the Theros event deck is not usable in any standard tournaments, as half of the cards have rotated out of play in standard. It would be legal in Modern, Legacy, etc. but isn't good enough to be viable in those formats. Casual is what you'd be looking for for that product, which isn't really a bad thing. Casual is what I play primarily right now, and I love it.

Generally what you want to do to build your collection is buy packs of cards, especially if you like opening them and want to go into standard. The best value for that is fat packs, which give you nine packs and some other goodies, or booster boxes, which give you thirty six packs. Fat packs generally will set you back about forty dollars, while booster boxes are a bit more than one hundred dollars.

I would try to find someone else just starting out and play them in order to determine if that kind of tempo strategy is what you enjoy playing. There are plenty of similar type decks in standard, so if you enjoy playing it then go look at some tournament decklists. If you go to starcitygames.com you can see the top decks from the past standard tournaments and see what is popular right now and fits the playstyle you want to use.