Cheapest hero or class to make a viable competitive deck for.

I have Jarl right now, he's decently fun, I think I would probably prefer wizard or maybe runeblade where I can do a mix of damages, boltyn seems cool as well. Kano seems nice with the instants. Main thing is who can I most cheaply build a competitive deck for, difficulty doesn't really matter I am fine with struggling and sticking with something. Also doesn't have to be completely meta right now. Appreciate any guidance and help thanks.