I have some ok cards.. I want something thats not gonna be 2 expensive to were i have 2 buy alot of gems to finish it.. I been collecting dark and zombies and warriors so far..
Do you have gozuki and samurai skull? Vampire minibox deck is one option. Since you say you have zombies card and minibox not that expensive compared to main box.
I'm f2p and I spent my gems on the new main box so I do not have vampire deck, but I can say 1 of each is not enough. You need at least 3-4 copies of them to consistently send dog/ bat into grave.
And based on my understanding it's quite competitive but I can't say how strong they stand in current meta.
Us f2ps need to know how to manage gems. Save them in large amount then go for a single main or mini box. No point spending only 10 packs on every box.
When they expiring? If can, wait and see how the next mini box performs.