He is pro priest indeed. And he building a tanky one! Level 69 going 70 now I believe.
Very common for low zeny earners to try farm card themselves, but it really depends on the card/monster rarity.
Have to remember that card drop rates are 0.01%, meaning hitting 10,000 of the same monster will grant you 1 card.
Its better to farm zeny off loot or other good maps and then make profit from the drop. With the profit, you can buy the card you always wanted.
e.g. I wanted to get infiltrator for my assassin, but farming nightmare is very hard for a low level sin. The market price for infil was 1.5m a few days ago. So I gathered loot averaging 120k-180k per hour at ayothaya. Then I farmed at kobold map, killing more than 2000 kobolds for 2 days. I was lucky to get a card from it and sold it off for 600k. From the total, i eventually got my infiltrator which seems more possible than grinding purely on Nightmare.
For Vitata and Creamy card, it is possible to farm for the cards, but don't put any high expectation to find them on first day. Just focus on collecting loot and keeping a consistent pace throughout the map. Optimize the pathing so you don't miss any spots on the map and find a good time when there is less competition from other players. I find that 8pm onwards is a bad time to go farming on most popular maps. Best is in the morning, as well as in the evening between 6pm-8pm.
been killing farming elder willow resin for zeny, more than 20,000 already still not a single card