My MacBook screen Is cracked

The actual cost will depend on a number of factors which you didn't provide in your post:

1. The actual model of your MacBook.
2. If there are any other damages besides the cracked screen.
3. If you purchase an AppleCare+ plan and it is still active. In the U.S. screen replacement costs are around $99.
4. Where you are located.

Regardless, the following links should help:

• Contact Apple for support and service - Apple Support
• AppleCare+ for Mac - Apple Support
• Check Your Service and Support Coverage - Apple Support
• Genius Bar Reservation and Apple Support Options - Apple