Y’know, the Get Out Of Hell Free cards have been going strong for a few years now. So sure, go ahead. Even better if you DON’T claim to actually deliver.
As Heinlein wrote, "Intangibles are the most honest merchandise anyone can sell. They are always worth whatever you are willing to pay for them and they never wear out. You can take them to your grave untarnished. "
This reminds me of something I read somewhere. It was a joke, I think.
The idea was that you give this “investment company” a pile of money to keep in an interest-bearing account. In return, the company gives you a secret account number and password. Then you die. Well, maybe not right away, but eventually, anyway.
After you are reincarnated, you get yourself hypnotized and regressed to your past life. You can then recall the account number and password you were given which you can use to reclaim the proceeds of your previous-life investment from the company. The compound interest will have added up and you can live your new life in luxury. Sort of life-after-death insurance.
What really, err, killed me was the slogan, “The longer you’re gone, the more you’ll have when you come back.”
As I said, this was supposed to be a joke but now that I think about it . . .
Plain language: You sinned and you should be punished. Now, God forgives when you ask, but you still need to be punished – out of divine justice, of course. If you don’t suffer enough because of your sins while here on earth, you’ll have to make up through suffering temporarily in purgatory in the afterlife on your way to heaven. Indulgences are practices and disciplines which reduce or take away completely (partial or plenary remission of temporal punishment) the penalties coming to you. You can also do these practices and apply the ‘indulgence’ to other people, living or dead (in purgatory).
Plain language: God gives grace freely. If you try to profit off of that, he’s gonna get you. ‘Simony’ is the name of profiting off of grace. Since indulgences are graces (i.e., literally free gifts) from God, selling them would be Simony, an objective evil.
The problem is that some indulgences involved almsgiving, which is supposed to be giving money to the poor. It evolved to also donating to the Church in order to support the work of the Church which is to help the poor. Unfortunately, the system got abused in the middle ages as almsgiving indulgences to the Church were used for grand building projects and lining the pockets of grafting clergy. This was seen (and rightly so in many cases) as Simony.
Plain language: We’ve got cognitive dissonance between the medieval idea that we still need to get punished for our sins, even the forgiven ones and the teaching of free grace, which includes free forgiveness of sins. (Not to mention the numerous Gospel passages where Jesus forgives and assures salvation without requiring one to ‘do the time’ of being punished for sins.)
Needless to say, indulgences in the Church are played down and are only the concern of hard core conservative Catholics.
So, WRT to the OP: Not only can’t you sell indulgences within the RCC (if you do there are penalties for doing so), but unless you’ve been specifically given the power, you can’t even give 'em out for free.
Peace.