Blessed are ye, when men shall revile you, and persecute you, and shall say all manner of evil against you falsely, for my sake. --Jesus Christ (Matthew 5:11)
Mary of Magdala gets a bad rap in modern culture. Many, even those raised in the church, have long supposed that this Mary was of unsavory character, probably a prostitute. There is nothing whatsoever mentioned in the New Testament to support this conjecture.
Let me say up front that even were her character depraved God's grace would have flowed to her anyway. For example, note the woman taken in the act of adultery (John 8). This woman is not identified and perhaps some confuse her with Mary Magdalene. Jesus did not condemn her but in an act of grace adjured her to go and sin no more. That grace is available to all.
When Mary of Magdala met Jesus she was possessed of seven demons which Christ cast out, healing her of her turmoil. Matthew 27 tells us that Mary followed Jesus from Galilee, ministering to him. Luke 8 says that certain women healed of evil spirits and Mary of Magdala who had seven demons were Christ-followers, that is they were disciples. Named here with this Mary are Joanna and Susanna who, we are told, "ministered to Jesus with their substance." Thus it is reasonable to conclude that Mary was reasonably well-to-do and had no family obligations to tie her down, as we might assume for the other women referred to here as well.
Mary of Magdala was one of the three Marys who stood before the cross. (John 18:25) She followed Jesus's body to the sepulchre so that she would know where he was laid. She later returned to treat the body with spices to find instead the empty tomb, and there she met Jesus who was risen from the dead. He commissioned her to go "tell the others" making her the first herald of His resurrection. The eleven, as we presently see, were at best reluctant to believe and indeed were doubtful and skeptical.
We do not know the occupation of Mary before she became a disciple, nor what the source of her income was. We do know she was a tortured soul who was freed from her bondage by Jesus Christ, as we all can be freed from whatsoever tortures our souls.
I think the "harlot" speculation is unfounded. What we know for certain is that Mary Magdalene was a faithful follower of Jesus Christ.
Scripture references to Mary Magdalene: Matthew 27:56, 61; 28:1; Mark 15:40, 47; 16:1-19; Luke 8:2; 24:10; John 19:25; 20:1-18.