There are a lot of different types of PDO threads. The cost depends on the length of the thread and whether it is smooth, twisted, or barbed. It also depends on the treatment area and amount of threads. On average I would say anywhere from $1000-5000.
Thread lifts (contour lift) use permanent sutures that are placed under the skin. The names change based on marketing but the anatomical principle is the same. The results are temporary because they do not access the prime issue with ageing: Descent of the structures that contain muscles (fascia). In a facelift, the main fascial system is elevated and sutured to another fascial system which provides longer-lasting results because this is the strength layer. While people are a bit anxious about getting a facelift, it has lasted for more than 30 years because is addresses the anatomy of ageing not the marketing hype of the time. In the thread lift only the skin is elevated and as we all know, skin is elastic and over time sags. The procedure can cost anywhere from $3-$6000 depending on your geographic locale. As I mentioned, the sutures are permanent and if placed to superficial can cause irritation to the skin. Good technique is always critical to the success of any surgical procedure. See a board certified plastic surgeon to assess what is best for you.