Buying A Hair Replacement

You Get What You Pay For
Think of a hair system as you would a new suit, as something to compliment your appearance. 
If you visit a tailor to have a suit made, he would take your precise measurements, inquire as to your intended use for the outfit, and then, together, you would select the cloth for the garment. After you left his shop, he would spend hours carefully sewing the suit to meet your specifications.
If the price of a tailored suit were above your means, but you still desired quality, chances are your next choice would be a selection from a reputable men's store. You would have several ready ready-made outfits from which to chose, most of which would be carefully-sewn copies of creations by well-known designers. Of course, the fit wouldn't be as perfect as that of a tailor-made suit, but most of these stores have someone available to make required alterations, enabling you to still be a well-dressed man. 
The final alternative available to you would be to settle for a ready-made suit off the rack in some discount house. In most cases an alterations man wouldn't be on hand, so you would have to settle for a suit closest to, but not exactly, your size. More than likely, this would not be a suit in which you would gain extra pride by simply feeling its cloth or by examining its workmanship, but at least it would serve its purpose. Your outfit would be another one of many mass-produced garments that is just a suit, nothing more.
And so it is with hairpieces. They range from the tailor-made exclusives all the way to those that will just get by. If you are concerned enough about your appearance to even consider buying a hair replacement, you should ask for one that is the closest to your natural hair as possible, one that will serve you well and be a wise investment. 
remember a hair replacement system should be the most personal and individual component of your wardrobe.