Ebay can be pricey, even outrageous, but don't discount it for hard to find parts. If you're patient, and don't need to buy the first time your item comes up for sale, you can find bargains. I've found items for my '60 220S Fintail such as a complete set of nice front and rear bumpers, including shipping from California, for $170, the rear pillar chrome 'boomerangs' for $19, a decent pair of sunvisors for $24, an original, working Blaupunkt AM tube radio, with correct faceplate and knobs, for $11.

My book 'Mercedes-Benz Production Models - 1946-1975' by W. Robert Nitske, gives the East coast base price for the 1968 6 cylnder 280SE sedan at $6222. West coast price was about $110 more.
By late 1971, the East coast price for the 6 cylinder 280SE was up to $9546, including automatic transmission.
The highest price 280SE was the 1971 3.5 V8 Convertible at $14509.

Happy Motoring, Mark

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DrDKW