It's an AGP card, which is the most powerful AGP card in the world, that's why its price is inflated: people who have old PCs with pentium 4, etc, and don't want to upgrade their whole PC, that card is the best they can get.
The HD 4650 you listed, is an AGP card, and since it isn't vastly produced/manufactured anymore, they'll tend tom cost more.
For example, my CPU (Core 2 Duo E7500) is old tech these days, and they cost more than you think. It costs around some $140 or so. For the same price, you can get an i3 2100 or an AMD Phenom II X 4 955, which are better CPUs.