September 19, 2022 (edited) , KOに번역する (번역を見せる) , ENから번역されました (원본을 보여주는)
Without any purchase, not that I know of.
However, sometimes the games let you get free cards. But you have to pay to play any game.
Often, there is the possibility to get free credits as a bonus for purchasing a large package of credits. At the moment, one can buy 500 credits AND get an extra 100 credits free.
Right now, one can play the game 'Wheel of bargains' and buy cards for a percentage off the normal price (and the user discount), and even possibly win a free card.
Right now, the games named 'Triple Chance' are three separate games. One can win free cards in any of these games.
note: this does not mean that one will win a free card; only the possibility of such happening.
You must spend credits in order to play any game, and you may come out ahead (more credits won than spent) or not. If you play, know that you may get cards you do not like.