Pricing Rule for Shop

My Customer has 3 Online Shops.

All Items and Conditions are set in ERPNext…

How can i deploy pricing Rules to these webshops ? or from other erp i know there has a price-api where conditions and pricings can be load from…

in the other hand how can i check prices apply correctly within erp next ? always open salesorder and test it with these ? If this the way i will build a app for quick price checkings maybe for the sales team

thx