I regularly take down high-end decks using six silver cards. Yep, six lowly silver cards. I use three Bear Warriors and three heals, and I constantly take down decks that have legend and epic level cards in them. I just faced Vanra, who threw a whole deck of level 30 epics and legendaries my way, and I would have won if the clock didn't run out at 99%. Granted, I did have to throw in two gold cards to get that far, but four silvers and two golds vs. all purples and epics, and I held my own, I would say that isn't too bad.
There are some advantages to this.
1) The CAP is only 12, while most people put together decks whose CAP is closer to 20-ish. When you win, you get a nice little experience bonus from that. With a lower CAP, you get fighting priority and more fights in because you are only burning through you energy 12 at a time, instead of nearly twice that with other strategies.
2) When you go into card battle, you aren't risking near as much. I just fought somebody with 1 legendary, 2 diamond, and 3 gold cards... and I won! I felt kind of bad, I got all those cards, but all I risked were six low-level cards. Heck, if I had lose, it would have only cost me 2,550 gold to revise my entire deck, all while having the potential to win some pretty nice cards. In poker, this is like considering pot odds. I'll take a long shot, because the bears surprise me sometimes and I can certainly get fair ahead.
3) This strategy allows for some flexibility while going into card battle mode. Let's say that no matter what, your first four cards are going to be two bears and two heals, and then analyze your opponents cards. If you see a bunch of trigger cards, maybe one of your last two cards will be a trap detector. Or if you see a few heavy hitters, a shield can serve you well. Usually, I stick with the 3 bears and 3 heals, but sometimes throwing in a different variable when you know what you are up against can make a huge difference.
4) They are only silver cards, which makes them cheaper to enhance. As you win some battles, keep a hold of the cards you win that you like, e.g., legendary cards, heal cards (they are in most hands you face), new bears, and cards you may use in the future. Half the cards you win you can usually sacrifice into rubies. Use those rubies to upgrade your bears and heals. Currently my heals are at level 40 (max) and my bears are at level 38 (almost max). Most of the rubies come from sacrificing from my wins and working my way to 8,000 gold and buying 200 in a shot. When I win 70% of my matches, getting there happens pretty quick. When my bears do make it to level 40, I'll be working on my Gargoyle next.
I snicker anytime I go against hands that are made up of less than level 10 cards. I win 90% of those fights, it doesn't matter which cards are played.So you don't want to spend money on the game, or can't spend money, that is fine. Go with this strategy, and before you know it you'll be winning some legend-level cards that you can have to keep in your hand.
Good luck!
-Pr0digy