Recently I am focusing on a way to sync the price and coupon from two or more shopify store.
here is the summary.
In fact, the best way to do such thing is that shopify support the callback function when the price or coupon changes, but indeed there is no way.
So we have to do some sync job repeatedly in a fixed time like 30 minutes .
The job was separated to three step.
First, we should get all the product of the source shopify store, use this api .You could filter the product by the active status or other things.
Then we should traverse the variants of product, then set price , stock or something to the target shopify site by this api
PS. There is no way to search what discount one product is using, You have to check it by yourself.