(Those in the picture are an example and are not mine, I'm not that lucky, don't go crazy now :)
This is going to be short and sweet.
Renting for power at the end of the season is not the most pleasant experience if you want to complete your daily quests at the intended league , cough gold. To a point that it is not possible to recuperate the DEC through playing. This is my first time doing this, usually I bite the bullet and rent what little power I needed to get to silver 3 and play until I've compensated for the rent. Nowadays I can do this without renting but I don't have enough to jump the next tier so I rent out whatever power I don't need and leave myself just enough so I can be at Silver 3 at the end of the season.
Renting out your cards at the last day is just about 10 times more expensive than through out the rest of the season. This gives you some pocket change to get a couple of more cards. Every little bit helps and over time it helps a lot.
Let me know in the comments below what is your end of season strategy!
Wish you luck with your renting and most importantly - the chests at the end of the season!