ERPAG allows you to have different prices for different customers by using the price tiers option. You can do that by going to:
Sales > Price tiers
When you open the Price Tiers, you will that ERPAG has already set two different price tiers: retailers and distributors. You can add additional price tiers by using the 'Add new' option.
When you open a price tier, in the item line, you will be able to choose the wanted products from the drop down menu.
Once you start choosing the products, the default price column will be automatically populated. That column represents the price you have set up for that particular product in your inventory.
The selling price column is where you need to define the wanted price for that price tier.
Once you are done and the price tier is saved, you can proceed by adding the created price tier to the wanted customer.
This can be done by choosing from the price tier field in each of the customers, or even from the customers list by using the bulk action.