I had FUT done to fix my hairline, and I've been very happy with the results. The only scar is a line on the back of my head, the "donor site," but it's completely invisible with my long hair. There's no scarring at the recipient area.
There was, however, a period of time after the procedure where it was obvious I'd had it done. A lot of redness for the first couple weeks. After that, as everything settled down and the transplanted follicles started to fall out (perfectly normal) it was easy to hide just by hair style. New hairs started growing in around 3 months post-op, and by 6 months post-op I had no problem tying my hair back.
Make sure you go to someone who specializes in this procedure. You want to make sure they understand things like proper density, appropriate irregularities in the hairline itself, and the fact that hairs tend to come out of the scalp at certain angles.
I'd guess you're looking at 2k to 4k follicular units, which could run $6k-$10k.