As the invitation indicates, the prices are unimportant. Every requested gift includes the name of a chemical element, and the quantities requested (1 through 9) suggest an order:
Silver
Titanium
Iron
Tin
Copper
Helium
Iron
Nickel
Gold
We hope you appreciated the idea that Franklin and Dee would probably need some STITCHING on their wedding day! We were also particularly tickled that our list of wedding gifts included a "Two-Timer".