"Compare At" pricing in Shopify is an option that allows you to set your pricing to a sale price, and then keep your original price in the "Compare At" field. This allows your customers to easily see their savings on your Shopify items.
Leading practice for setting up Compare At pricing is to set your Compare At prices using Price Levels in NetSuite, and then sync those to Shopify. The Price field should be mapped to the Sale Price level and the compare at field should be mapped to the standard Price field.
In the left hand nav bar, click "Shopify", then "Mappings", then "Products". Click "Add Mapping" on the top right, then select "compare_at_pricing" from the "Standard" menu.
In the mapping window, enter the field ID for your Price Level/Field, and check the box if you use quantity based price levels. Then click "Save Changes", and then "Save".