Thank you for the question. You will have to figure out how much botox costs per unit in your area and how many units you would need for the result that you want. Average botox per unit is somewhere between 6-12 dollars depending on surgeon/spa and area of the country. Most people start out with about 30-45 units for the frown lines (corrugator) and the forehead lines (frontalis).
All the best,
Dr Remus Repta
Web reference: http://www.aaaplasticsurgery.com/medical-spa/