An easy and efficient way to update products and product variants prices is using the price list. First, you need to activate the price list setting in odoo: Sales > configurations > price list 

You have 2 kind of price lists possible:

• multiple prices per product > the one we will use here

• Advanced price list rules 

Check the video here and the high level steps below

We will create a price list template import to update prices in bulk

• Activate the “multiple prices per product” (Sales > configurations > pricelist > multiple prices per product) 

• In excel create your pricelist with the below column:

• Id > external id of your pricelist > don’t copy the external ID value for each row, you’ll otherwise create new price lists

• Name > name of price list > don’t copy the value for each row, you’ll otherwise create new price lists

• item_ids/id > external id of the line you want to update when exporting/importing > MANDATORY otherwise odoo will create duplicate lines of the ones existing in your pricelist

• item_ids/product_tmpl_id/id > id of the article/product

• item_ids/product_id/id > id of the variants from the product. You can retrieve the variant external id on the product.product model (sales > product > product variant)

• item_ids/fixed_price > price of the product or product variant 

• Import your file in the product.pricelist model (sales > products > price list)

And that's it :)