Oh, wow. I am not going to be making a lot of friends in this thread... I don't know everything about this game, but we've got a faulty premise and some slightly off answers (mostly because they accepted the faulty premise). Welcome to the game, MightyKawa, and these message boards. I hope you're a better person than I am, and more willing/able to accept correction.
The
short version is that, not only can Pokémon-EX/GX be beaten, some of these cards are really bad while most are mediocre (like Blastoise-EX). For the
longer version:
There are no Pokémon-EX/GX in the Theme Format, which only allows Theme Decks: please note that not all Pre-Constructed decks are classified as "Theme Decks" (by the PTCGO, if not by Pokémon in general) and that there are some PTCGO exclusive decks. If you're new to the PTCGO,
start with the Trainer Challenge mode. This is a single player mode that will help you get used to the PTCGO interface, contains some easy unlockables,
and will show you that Pokémon-EX/GX aren't invincible. How so? The very artificial, but not very intelligent CPU opponent's sometimes have them, and yet this is the super-beginner mode, where you may only use Theme Decks.
There are balance issues within the Pokémon TCG, but they are
not Limited to a particular Type, Stage, or being a Pokémon-EX/GX. Are some Pokémon-EX/GX too powerful for the game's own good?
Yes. Some are rubbish, though, and the same holds true for almost every other combination of Stage, Type, and mechanic. If you're having trouble beating
any Pokémon-EX/GX, it means you need to improve your deck, improve your skills, or improve both. Pokémon-EX/GX are worth
two Prizes, that means you can lose
two Pokémon scoring the KO still break even, while scoring the KO with one Pokémon will allow you to take the lead. Some cards have potent, anti-Pokémon-EX/GX effects, but a lot of it is just learning how to approach the situation and - of course, obtaining a better card pool.
How do you affordably get more cards in the PTCGO?
In one sense, you don't; it is going to cost you either time or money,
however, it is possible to build competitive decks on the PTCGO
without investing actual money into the game. I know, because that is how I use the PTCGO; I've spent
no money on it, merely invested a lot of time. Nor am I a genius player who wins all the time; I don't track it, but I estimate that I win between 40% to 60% of the time. The big issue here is learning that
1) Some packs can be traded, while others are "trade-locked".
2) Unless you're "rich" or intentionally investing in becoming a trader, you
do not open any pack you can trade.
3) Use non-tradeable rewards to reduce the need for tradeable versions of cards as best you can.
4) Earn stuff you can trade through certain in game rewards, most notably, by winning tournaments. There
are Theme Format tournaments!
5) Learn the current trade rate for both booster packs and cards; not all boosters are valued equally!
6) Learn the basics of trading well; being patient and looking for good deals is a big part!
Last but not
but not least, not all Theme Decks are equal. Some are
really bad and
none are competitive outside of the Theme Format, but most of the SM-era Theme Decks are at least "decent" for the Theme Deck mode. Unless you already have enough tokens - each will cost you 500 - then you'll have to make do with what you've got. Still, it shouldn't take too long to grind that initial 500, and by then, you can get the "Mach Strike" Theme Deck from SM - Ultra Prism. If you do have enough now, then go for the "Luminous Frost" or "Rock Steady". They are the most reliable of the Theme Decks, not too hard to learn, but still among the best in terms of offense as well. Some of the others are better
but are a bit less reliable or tricky to learn (at least, when you're new).