Good Gawd, are you talking the wipers themselves, or replacement rubber blades? I paid $6 per side at Walmart yesterday for mine, and the metal assemblies are a dime a dozen at a pickapart yard. For $400, you can send them away to get rechromed, AND get money back.
Ok then, these are Bosch blades with Bosch assembly. I bought here in Australia a set of cheap REPCO replacements and they eventually wear and scratch your windscreen. The originals cost so much because they have run out of stock, I already mentioned this.
I have tried three different types and they are all shit compared with these.
I tried BURSONS, REPCO and a cheap BOSCH type that any MECHANIC who knows about Mercedes will tell you that the ones from these stores are cheaps, only the originals with the metal strips inside are worth it.
Only maybe some FORD type blades will fit the original Bosch wipers, thats also the metal strip which makes it last longer, and they are about $10 - 20 US.
Original metal strips that you will not find at cheap bargain bins brand new will cost about $30 - 40 US each.
I have done a bit of research on this, there is nothing worse for a classic car than a set of wipers that scratch and screech when they are used.