Most ecommerce solutions don’t provide this details to retailtower, to solve it,a) Define the shipping cost at your channel merchant center, Google for example go to Settings > Tax and shipping. if you don’t change shipping, just type 0.00
b) Secondly use the advance insert option on the products page of retailtower to insert the shipping cost for the products. Use the sort option to group products before inserting if you have different shipping cost for different product groups. This is the most recommended approach since the editing applies for other channels Eg. 5.00 can be inserted in the shipping column of your products which attract 5.00 units of your store currency.