If you have diffuse hair loss, you may not be the best candidate for surgery. You must also consider that normal hair density is about 200 hairs in a square centimeter for an average non-balding person who has about 100,000 hairs.
These hairs have taken on a J shape which means that the grafts were kinked when then were placed by the surgical team. There is always a question if these grafts will grow out as normally as those without the kink.
The cost of hair transplant or any cosmetic surgery varies widely between doctors or clinics. The method of harvesting and technique will also play a factor. It is best to start by seeing a doctor for a consultation.