The shipping prices let you set shipping prices per product based on the product price.
The shipping field on the list of export fields must be the custom_shipping field.
There are 3 fields that need to be filled for a shipping price to work:
When doing a Google Base export the export field will look like this:
|Field name||Default value||Column header|
The shipping prices can be configured as:
|Price from||Price to||Value|
When the export is performed, the g:shipping value is based on the product price. If the price is 500, the g:shipping will get a value of US:UPS Ground:8.00. In case no shipping price can be found the default value of US:UPS Ground:12.00 as specified in the export field will be used.