Mark 16:1 (NASB)
" When the Sabbath was over, Mary Magdalene, and Mary the mother of [a]James, and Salome, bought spices, so that they might come and anoint Him."
Luke 23:55-56 (NASB)
55 "Now the women who had come with Him out of Galilee followed, and saw the tomb and how His body was laid. 56 Then they returned and prepared spices and perfumes. And on the Sabbath they rested according to the commandment."
Jesus' body was prepared for the burial according to the custom of the Jews.
John 19:39-40 (NASB)
39 Nicodemus, who had first come to Him by night, also came, bringing a mixture of myrrh and aloes, about a hundred pounds weight. 40 So they took the body of Jesus and bound it in linen wrappings with the spices, as is the burial custom of the Jews.
Jesus died about three hours before the Sabbath and the burial task was probably done hastily. After the Sabbath the women returned to add more spices and oils, likely they would apply the spices and oils over the wrapped body.
Luke 23:50-56 (NASB)
Jesus Is Buried
50 "And a man named Joseph, who was a member of the Council, a good and righteous man 51 (he had not consented to their plan and action), a man from Arimathea, a city of the Jews, who was waiting for the kingdom of God; 52 this man went to Pilate and asked for the body of Jesus. 53 And he took it down and wrapped it in a linen cloth, and laid Him in a tomb cut into the rock, where no one had ever lain. 54 It was the preparation day, and the Sabbath was about to begin. 55 Now the women who had come with Him out of Galilee followed, and saw the tomb and how His body was laid. 56 Then they returned and prepared spices and perfumes. And on the Sabbath they rested according to the commandment."
Luke 24:1 (NASB)
1 "But on the first day of the week, at early dawn, they came to the tomb bringing the spices which they had prepared."
Conclusion
There is no contradiction. Jesus died just before the Sabbath was about to begin, ( Luke 23:54) the preparation for the burial was hastily carried out according to the custom of the Jews, and on the first day of the week (the day after the Sabbath) the women returned to add more spices and oils to the body.(Luke 24:1)