If you have many variants to update, you can use a CSV import to complete the task with a single process.
To do so, navigate to Inventory > Price Lists, then click to open the price list you need to update.
Once the price list is displayed, click the Update Price List via the top-right corner's CSV button.
If you don't yet have a CSV file to update, select the No, I need to download a template to fill in the option.
Alternatively, if you already have a CSV file ready to upload, skip ahead to Uploading your edited CSV file.
Next, you'll be asked to select which variant attributes to include in the CSV file. By default, the required attributes for the chosen price list are selected. If you wish to update more than one price list with a single CSV file, select the additional price list as required.
Click the BUILD CSV TEMPLATE button, then, when ready, click the DOWNLOAD PRODUCT SHEET option.
Once downloaded, edit the data as needed, then select the UPLOAD FILLED CSV button.
Uploading your edited CSV file
Once you've downloaded and edited your price list CSV, it's time to upload it! Either select the UPLOAD FILLED CSV option presented when exporting the original CSV or start the process again and select the Yes I have a spreadsheet with an updated price list ready for upload option.
You can either drag your CSV file into the grey upload area or click to select the file from your device from the upload page.
When ready, so proceed, click the green UPLOAD option.
QuickBooks Commerce will process the CSV file then ask you to confirm the changes. If you're happy to update, click the YES, THIS IS CORRECT > option. Your changes will now be uploaded.
If there are any issues with your CSV file that would prevent QuickBooks Commerce from correctly processing the changes, a breakdown will be displayed. For example: 
In some instances, the 'DOWNLOAD SPREADSHEET WITH ERRORS' button will be displayed. Click to download a CSV file detailing each of the errors in your original CSV file and try uploading again.
Edit the file to correct the issues and proceed with the upload by clicking the re-upload the corrected spreadsheet option or starting the process from the beginning.