Older hardware = Costs more
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.