Feature Request - Bulk Update Product Prices by % or Fixed Value

As a business, I would like an option to update all my products in my inventory by a % or Fixed Value to increase or decrease prices in bulk. 

It would also be great to extend this functionality to update pricing by brand or category. 

The other option would be to download my product list - change the pricing field by the values I would like to see at retail and re-upload the data with the new pricing.