Buying A Booster Box?

The more I've been playing Pokémon cards, the more I've been wanting to buy packs of them.  I've always traded and bought single cards, but it's not always easy trading, and after awhile, paying a lot for rare single cards is just too expensive.  That's why recently, I've been looking at booster boxes of cards.  In Pokémon, their boxes usually cost around $100 for 36 packs, which sounds like a lot, but when you consider that normally a pack costs between $4-5, the savings adds up.  It's just such a huge investment, and for someone like me who is a casual gamer and low on funds, I wonder if it is worth it?  Part of me says no, but a large part of me is excited at the possibility of opening so many packs.  Especially if I decide to get the Plasma Blast box or the Wild Blaze box, which isn't coming out till May.  The Plasma Blast set has Genesect EX and Virizion EX, two of the best and rarest cards, that I would want if I made a grass themed deck, but if I got the new one, I'd have a chance of getting the new Charizard EX cards, which I could add to my deck.  A tough decision for sure, but what would you guys suggest I do? 

A booster box might be in my future, but which one should I get?