From BusinessWeek's Arik Hesseldahl:
All told, the cost of the shuffle's components, the headphones, and the packaging it ships in comes to $21.77, according to iSuppli's estimates. That's about 28% of the device's retail price. The smaller the component cost as a percentage of price, the higher the potential profit. This suggests the per-unit profit margin on the shuffle is higher than on other iPod models. The component cost for the first iPod touch released in 2007, for instance, amounted to about $147, or about 49% of its $299 retail price. The component cost of the third-generation iPod nano, also released in 2007, amounted to about 40% of its retail price.
Deconstructing Apple's Tiny iPod Shuffle [BusinessWeek]