WorkGuru allows you to update all product fields except for the SKU in bulk via a CSV file.   This is handy for ongoing product information such as price changes etc.    When importing products back into WorkGuru, if the SKU matches, it will update that product.  If it the SKU doesn't match it will add the products.

Export the existing product list from the products dashboard (Administration -> Products -> List Products -> Export Products). If you only need to update a subset of your products, you can use Advanced Export to only export a set list, such as just products from one supplier only.

Open the downloaded WorkGuruProductExport.csv file in your spreadsheet editor of choice.   Be aware of spreadsheet editors auto-formatting data fields (removing leading 0's, dates, barcodes etc).   It is recommended the spreadsheet is edited in plain text format if possible.  If you want to be 100% sure no data is auto-formatted, it is highly recommended you import the .csv instead of opening it in Excel or Google Sheets.

You can update every column in the export EXCEPT for the SKU.   For example, you can use your normal spreadsheet tools to increase the SellPrice by a required percentage etc.   When you have finished the changes, save or export the .csv.  NOTE:  You don't need to re-import all the rows in the spreadsheet, technically you can remove everything except for the rows you changed.   You do need to retain all the columns though.

From the product import page (Administration -> Products -> Import Products), or Import Products from the Actions menu.  

Click the Choose file button, select the updated product .csv and click Save to process the update.

WorkGuru will return to the products dashboard if the update has been successful.  Check an updated product to confirm.