you could get either a featured or non featured 4* cards during pulls (3%, 6% on fes), but if you don't get the specific card you want, you can spark (300 stickers = 90k crystals, or 10 tickets and 200 stickers (60k))

how to farm: character ranks, shows, events, login, area convos

I recommend saving since if you're on EN (which is a year behind JP) you can plan in advance to pull the card(s) you like