Well, assuming you really need injectors, my rebuilt BOSCH injectors were about $56-60 each and the labor to replace all of them was about $75.
Fastlane sells them for maybe less. Some people claim that the rebuilt Bosch injectors can sometimes be defective. See archives. I've had no problems.
My injectors were replaced under factory warranty when the car had about 5K miles or thereabouts. Because of noise.This last time they were replaced at about 145K miles.

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1979 300D 220 K miles
1995 C280 109 K miles
1992 Cadillac Eldorado Touring Coupe 57K miles SOLD
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1979 240D 140Kmiles (bought for parents) *SOLD.
SAN FRANCISCO/(*San Diego)
1989 300SE 148 K miles *SOLD