That's if you only want a neck mount. If you want one of the newer styles today or an ofset or pedestal mount, you really should start skinning all the way back at the buttocks. It's actually easier than starting behind the front legs, gets less hair all over your meat, and it ensures there's enough for the taxi. to work with.
I don't know about your taxidermist but I tell my clients to do a ring around where the rib cage comes together. That is plenty. Then ring the front legs, at the knee, then follow the back of the leg to the rib ring. Other than that, cut off 6" of the neck leaving it attached to the head. I really only need 3" but some guys can't tell 3" from 6" so I err on the larger size.
The most important thing is how you care for it before it goes to the taxidermist. Try not to drag it, you will break the hair. Try to get it in the freezer or to your taxidermist as soon as you can. Don't drive around showing it to the whole town. Take some pictures but the longer it is out, the more bacteria has a chance to work it's magic.
As far as price, in my region, as low as $165 to as high as $450.