The "Free Gift" Desire Amplifier

Act as a desire engineer. Help me write copy for a "Free Gift with Purchase" promotion that makes the free item sound so desirable it becomes the primary reason for purchasing.

• Main Product: [e.g., "Premium Face Serum"]
• Free Gift: [e.g., "A full-sized hydrating eye cream"]
• Minimum Spend: [e.g., "$80"]

Task: Write the promotional copy. Focus 70% of the copy on describing the free gift in luxurious, benefit-rich detail. Explain why it's valuable and how it complements the main product. The main product becomes the vehicle to get this amazing gift.