This is an accepted solution.
You can update those in bulk by navigating to Products > select all products > Edit products > adjust the prices. This will take some time, so the easiest way to update those in bulk will likely be to update them using a CSV file. You would export your products as a CSV file, update the pricing, and import it back into your store (to overwrite the originals). Alternatively, you can use an app such as Excelify to update those as well. Hope this helps!
My name is Alison, and I'm the Customer Success Specialist for Ablestar apps.
We have an app called the Bulk Editor (https://apps.shopify.com/bulk-product-editor) that can not only update products by spreadsheet, it can also schedule the edit, and the undo of the edit, which is very helpful when setting up and ending sales. It differs from the regular Shopify import in several ways:
The app also has a free version available that allows for 5 free in-app edits and 5 free spreadsheet edits a month. As long as you stay under the edit limit, you will not be charged (and you would be prompted before you went over the limit). Feel free to reach out to us at email@example.com if you have any questions.