How much itching should one expect after a forehead lift and what is a typical cost?

Forehead lifting and itching or hair loss? Itching is not common long term after a browlift but happens occasionally with both types of browlift-Endoscopic and Irregular Trichophytic Forehead Lift which we developed 40 years ago. Low hairline =endoscopic High hairline =Irregular Trichophytic Forehead Lift I have done hundreds of these without hair loss or a visible scar. 

There are basically two types of forehead lifts. The open forehead lift entails large incisions with skin removal and is always associated with numbness and itching in the forehead which can last for a year or longer. Because this approach has larger incisions the risk of hair loss is greater. The more modern approach to forehead lifting is the endoscopic forehead lift. This entails small, hidden incisions in the hair, no skin removal and much less risk of numbness and hair loss. 

 The itching that you are are referring to is the sensory nerves that are growing back together in the scalp  after the forehead lift. A forehead lift is only performed for patients who have low set eyebrows. In addition, a forehead lift  can accomplish adjusting eyebrow asymmetry, raising or lowering the hairline, and softening the vertical and horizontal lines in the forehead. For many before-and-after examples and our current price list  for forehead lifts, please see the link and the video below

Forehead lifts are done a variety of different ways with the risks being altered depending on the technique utilized.  Some of the more common ways are endoscopic, pretrichial (in front of the hairline) and coronal.  In patients with deep forehead creases, a direct skin excision can be performed.  With any browlift there will be a risk of numbness of the forehead though this is fairly low and usually temporary.  
The itchiness that occurs afterwards can be related to hyperactive nerves and swelling.  As the swelling subsides the itching usually resolves which takes anywhere between a few days and a couple of weeks, with some patients experiencing prolonged swelling though this is rare.
In terms of hair loss, the risk is entirely dependent on the approach and the design of the incision.  With a properly performed incision hair usually grows through the scar and hair loss is minimized, however if the same incision is performed poorly, hair loss can result.  So the risk is variable based on both incision placement and surgeon technique.  Your best bet to minimize risk of hair loss is to have a surgeon who frequently performs forehead lifts.
Cost is variable as well ranging from 3,000-10,000+ depending on region and surgeon.  Frequently, forehead lifts are performed with upper blepharoplasty which can increase the overall price.  
Good luck moving forward with your procedure!