● Luke 2:22-24 . . And when the days of her purification according to the law of Moses were accomplished, they brought him to Jerusalem, to present him to the Lord. (As it is written in the law of the Lord, Every male that openeth the womb shall be called holy to the Lord) And to offer a sacrifice according to that which is said in the law of the Lord: a pair of turtledoves, or two young pigeons.
The birds were for Jesus' mom (Lev 12:6-8). They were a "sin" offering; but I don't think it would be wise to conclude from the wording of Leviticus that Jesus' mom was a sinner because whether sinner or saint, God required it of Moses' people; take for example Matt 13:13-15 where it's said:
"Then Jesus came from Galilee to the Jordan to be baptized by John. But John tried to deter him, saying, "I need to be baptized by you, and do you come to me? Jesus replied: Let it be so now; it is proper for us to do this to fulfill all righteousness. Then John consented."
John's baptism was "unto repentance" (Matt 3:11). Well; surely Jesus needed no repentance; he was a saint in the extreme sense of the word: i.e. Jesus was 110% sinless (John 8:29, 2Cor 5:21, Heb 4:15, and 1Pet 2:22). However, it was God's wishes that people in the Israel of that day submit to John's baptism regardless whether they needed it-- not only because it was God's wishes, but by doing so they publically acknowledged that repentance is a good thing.
In other words: Jesus' mom brought those birds; not because she was a sinner, but primarily because it was the right thing for Jewish mothers to do.
Now, Jesus was circumcised on his eighth day (Luke 2:21). His mom brought her birds thirty-three days later (Lev 12:3-4). Along with the birds, she was supposed to bring a sum of money to redeem her boy (Num 18:15-16).
The redemption money was a buy-back; in other words: its purpose wasn't to save Jesus' soul from Hell; rather, the money was a ransom; so to speak. All the firstborn sons in Israel were God's private property to do with as He pleased. In other words: the boys were all born into slavery to God. The redemption money bought them their freedom.
It really wasn't all that much; just five shekels, after the shekel of the sanctuary, which is something like twenty gerahs per shekel (Ezek 45:12) roughly equivalent to 10 English pennyweights or 1/2 troy ounce of silver. So five shekels would be about equal to 2½ troy ounces. The price of silver as of Aug 05, 2020 was 27 US dollars per troy. So 2½ ounces troy would total about 67.50 US dollars (57.35 Euro).
I don't know the equivalent of $67.50 back in Mary's day but in our day, silver prices fluctuate due to the activity of investors; back in her day silver's value was no doubt strictly regulated by the government and thus probably worth a whole lots less than it is now.