THE UNKNOWN
The prices to rent these unlocked cards is very high at the moment.
Let's examine the summoners.
Price to unlock max level summoner = 24150 DEC.
The daily rental price looks to range from 30 - 200 DEC.
The best-case scenario, I feel the best summoners could settle in at 50 DEC per day max.
At 50 DEC per day, it would take 483 days to get your money back.
This would make it very much worth your time.
Realistically, 25 DEC is the high end of what to expect. This would take about 2.65 years to get your money back. (still a very good return on investment)
Let's do 10 DEC just because it is probably what will happen. (6.6 years to get your money back and then you still own the card.) This people, is still a good return on investment.
Remember, these are CHAOS LEGION reward cards. Chaos will be demoted to wild league upon the release of the next set of cards. Reducing further the pool of players that would even rent the card.
THE GOOD
Day one of unlocking cards was very much worth the time.
The summoner cards were selling fast and at good prices.
Lobb Lowland in particular was selling at 0.29. ~451 DEC.
The price to unlock rare cards is 200 DEC.
THE BAD
I was looking over my cards deciding if I would unlock any other random cards for the future.
I have several Gold foil common, rare, and epic cards that are essentially useless to me if I leave them locked. (I am leaving the regular cards locked, for my own use)
The market for Gold foil cards is virtually nonexistent. Don't waste your time here.