Once you are logged into your SkuGrid account, go to the Settings tab. Select Marketplaces , then eBay or Amazon ( depends which is your current marketplace ) and then select the country you are selling at. 

Let's take eBay US for example. Once you are into the Marketplace settings for eBay US , locate the Calculating eBay's Selling Price and click on the Switch To Wizard View button below ->

The Formula Wizard will pop up. Then locate the Include Supplier's Shipping In Calculations option and change it to Yes from the drop down menu. Save the change via the Close button. 

Force Recheck and Reprice to all available items would be a good idea after this action.