Could you have saved costs by reducing some of the cards you rent? Or only rent when a card reaches a specific value before you rent it?
Also, I wonder if you could benefit by renting 3 days after the start of Season when hopefully the better players have filtered upwards?
Nice summary.
Yes, I probably could reduce costs. There are a few cards that are key to combinations and strategies so that can also be difficult in places. I've found the cheapest rentals are available at season start.