Here is a guide where you can rent 100 DEC = 5K POWER.
First you need to use Laptop or Personal Computer.
Most of all the people want a gold foil card right?
Well here is a different approach
A lot of cards common once is worth 0.10 day rent which is 10 Power per card.
Here is my computation
10 x 100 CARDS = 1,000 POWER
0.10 DEC x 100 Cards = 10 DEC
Maximum renting a card is 45 so you just need to select everything to rent.
It's possible select 10 cards or 20 cards to avoid being getting someone first.
I'm pretty sure when this is posted some people will try this method instead of getting the Gold Foil cards