A cutting will start putting out roots in a week or so, but it takes 6-8 weeks for a seedling to come up to planting size.

I agree with spiced ham. For speed, a cutting's faster. You'll need to give it a week or so to develop new roots and start new growth before hardening them off if they haven't been.

If your tomatoes are already in the ground or outside in containers (already hardened off), you can just put the sucker into good planting soil, make sure it stays moist though not wet, and present it to your friend as ready to plant when it makes new growth!

Both anney and spiced ham are correct. As anney had mentioned, put them in some potting mix and keep them moist, but not wet...they will droop for 2 days or so, but will liven up and start looking happy.
Good thing about cuttings is that you can root some at the end of Summer for a Fall crop and they will be true to the parent.

Happy Gardening