typical cost of extension
1 A partial head of hair extensions typically costs between $150 and $300, plus the cost of the hair. 2  Total cost ranges from $400 to $800. 3  A full head of hair extensions (for fullness only) typically costs between $300 and $600, plus the cost of the hair. 4  Total cost ranges from $1,300 to $1,600. As hair grows, hair extensions will need to be taken out and reapplied; hair extensions usually last an average of four to six months. 2  This re-application will cost as much as the first for labor, but high-quality human hair usually can be reused.