There is a large difference between asking someone to name a price and asking someone to donate. In the first case you are forcing them to pay for a product (even if they pay $0). In the second case you are hoping they feel charitable.
The Humble Indie bundles come to mind as a nice way for people to name a price, given their popularity I'd guess they are doing something right.
The Humble Indie bundles come to mind as a nice way for people to name a price, given their popularity I'd guess they are doing something right.