Not sure how much repair is necessary, but I work for a home repair and painting company, so I looked up something similar for replacement that we did in the past year or so. We're on the pricier side, but I feel like the numbers give a decent breakdown.
For a new door, of reasonable quality, assuming it's door with frame, you're probably looking at $1,500.00 to $2,000.00 for a new door and labor.
That's likely assuming the following: 2 workers x 8.0 hours to remove and install new, trim out or finish around as necessary, $300-$500 for the door, and another $100-$200 for other materials, as/if necessary.
I hate my job.