How can I pull and edit catalog product prices using API?

I want to pull catalog products using an API ?
and I want to edit the product price in the catalog like i have a catalog called Designer I want to change the price for a product .

If its one product, just use admin.
If in bulk, I made windows app that will take exported product csv and change prices based on margins, do sales, and update Google Taxonomy. You can re-upload csv file