I've played thousands of games of Gods Unchained now. I've bought plenty of cards.

The decks I have that win the most are almost always based around strong, free cards I got in packs I got each time I leveled up.

You can go to https://gudecks.com/ to see current meta decks and stats and such, it's the site I use the most.

Gutools and Cardsunchained are also great sites you should check out to learn more and improve if you want to do that.