well i think it is between 60 to 70 dollars depending on the company.
It is better to buy from the original manufacturers for better results as after all its the question for your skin. I recommend following the instructions supplied with the product and see what happens. I started with only one of the products in time for a week before adding the second product, and only once a day until my skin adjusted to the system. If you just jump right and start using all the products at the same time you have side effects. I know, because this is what I did for the first time I used proactive ago. It is recommended to use oil free Moisturizer.

How do i use -  This product cleans deep below the surface remove impurities and break outs is going to happen at the start of treatment, once you past this bump in the road you will see an even more watered down clear skin if you medium to oily.

I use before I Moisturizer refining lotion. Where the use of only a few dots. There is long way.Proactiv works, but you have him a chance. Since most cleaning products are not exported to the PH level of your reactions to the switch. I used the product for more than a year and loved, but stopped and started breaking off. So I started again, even though the price is so high.