I’m fairly certain you have to spend at least 10 dollars to be eligible to earn booster pack drops, but if you just want the badges you can craft booster packs for less than 500 gems a pack, if you’re going to spend money, I’d recommend buying credits as they are harder to get for free and needed to unlock most models, and I believe you do get 1 or maybe more cards per 10 dollars you spend, but remember that your booster drop rate is based on your steam level and how many people are crafting the badges, so even if you do spend money, boosters for free to play games are still very rare to receive. I had to craft booster packs with gems to get most of the cards for my badges.