There is an interesting article on the BBC website today about how data from eBay has been used to evalulate the actual value of gift vouchers.
There is a vibrant secondary voucher for high street gift vouchers on eBay and research by Jennifer Pate has shown that these vouchers sell for approximately 20% below face value. The inference is that a gift voucher can only be exchanged for cash at this price and so giving a gift voucher is the same as giving 80% of the vouchers value in cash. I suppose this makes sense due to the flexibility of the asset, a gift voucher can only be used in one shop and so is less useful than cash. The original research can be found here.
I think that this research is also interesting as it shows how data from eBay can be used to answer economic questions. In my experience eBay is the only place where it is possible to get data about that real value of many commonly sold items.
I suppose it also highlights an opportunity for saving on purchases. If you can bothered, buying gift vouchers can save 20% on high street goods.