I need that if the buyer buys more than for ex (200) of one product from (201), he will pay cheaper the product. I explain till item (200) he will pay 2 dollars and from item (201) he will pay 1 dollar. Is that possible?
You didn't specify a Magento version, so I'll use Magento 1.14/1.9 as the basis of my answer; though, the same thing could be created for Magento 2.
Sounds like you want to use customer segmentation and a custom price rule for that segment.
Basically you would create a customer segment with the condition like:
Then you'd create a Shopping Cart Price Rule and specify the condition to be the customer segment you created:
Then just specify the product discount in the "Actions" tab.
The only downside is that the price won't change until it's in the cart. Otherwise, you'll need a custom module to add customer segments as a possible condition for Catalog Price Rules, or the module will have to change the price on its own based on customer segment.