Newbies' guide to renting!

I wanted to create a guide on how to increase the Collection Power to increase the player's rank limit.
Here's DEC burning chart:

It means that renting gold foil cards would be better than renting normal ones.

I would also recommend using this website:
https://monster-finder-d7d0d.web.app/

Created by @scrubles. I checked it out, and it will show you the estimated DEC value per monster:

The lowest-priced monster for rent right now, as of writing this post, is Cursed Slimeball which has the estimated DEC of:

So, if you calculate, renting low-value gold cards would save you a lot of DEC, while raising your Collective power. Happy grinding everyone!