Of course many are going with the "three gift" idea - something they need, something to read and something they want. I'd classify a carseat as a need!
The First Years True Fit IAlert C685 Car Seat, Black & Gray is on sale for 51% off on Amazon. It is $399 at Diapers.com.
Save on the Graco Size4Me 65 Convertible Car Seat, Go Green. THe Nyssa color is also on sale, but not as much.
Save $110 on Diono Radian RXT Convertible Car Seat, Trekk! Others are on sale but savings are not as much.