I've been meaning to start this thread with more research for a while but since
@IshChayil is briefly with us and I want his input I'm just going to throw it out there.
The Law says that every firstborn male from a woman (so not the man's firstborn son but the woman's. I have sons by three women, each of which was the first son of that woman. All three of those sons fall in to this category not just my firstborn) is dedicated to God and must be redeemed. What does this mean practically? Traditions as well as scripture is being sought.
OK so there are a few more things to check.
Did any of your gals ever have a miscarriage BEFORE they had your sons?
It's only the "peter rechem" so the first to pass through the womb literally?. So if there were any miscarriages or any live daughters born first, then that means that son that came later is not the first through the womb.
NOw, if each of these guys was the first human to pass through the womb then they belong to the Cohanim (the sons of Aharon) and need to be redeemed.
In Jewish culture this means we have to give loot to some lucky bastard who is a descendant of Aaron. Usually people buy special silver shekhels for it and pay the kohen in a short procedure known as "Pidyon haben" (redemption of the son). Uusally, if the Kohein is cool he'll give some of the money back for the boy's religious education "buying" a seat at the bar mitzvah.
There's more to this. The history has to do with how we (native born and adopted alike) were ransomed from Egypt and there wasn't enough paid back to Hashem so now we need to redeem our firstborns (just as He redeemed His firstborn, Israel from Egypt).
If you know a Cohein to qualify he has to be: Not married to a convert or the daughter / grand daughter of a convert (I understand this to mean convert to Judaism or Christianity as Christianity is "grafted in" so still counts). So if if his wife's grandma was a Buddist he no longer has the Kahuna "priesthood". This has to be true for 3 generations of his family.
So if you know someone like that you can pay him then your kids are not "slaves" to the priesthood; i.e. Hashem via proxy.
Now I see this as Aaron's right so I don't think we can generalize this away to mean ministers or rabbis it's stealing from Aaron if we do that.
Usually a first born and first to pass through the womb is redeemed as a baby but he can be redeemed at any time in his life. he can also redeem himself if a parent didn't do it.
Hope this helps or at least gets stuff started (we don't mean salvation folks by "redeemed" in this context).