To showcase both the regular and sale prices of your products on Google Merchant using the the FeedFusion: Product Feed Sync app, follow these steps:

1. Add a `compare_price` field to your template. For a visual guide, refer to this screenshot:

2. Use the Min Variant Compare at Price attribute for the `compare_price` field. 

By following these instructions, your feed will display both the regular and sale prices, as shown in this illustration