Partly as above. MB tex is hard wearing, but most people want leather. Wiring looms notoriously degrade and are expensive, so check the history (and loom at the connections). Also have a look for oil leaks, as head gaskets are a common job on 104 engines, but they usually carry on regardless.
The 124 suffers with rust on the front wings and under the headlights, and the estates suffer around the window frames of the cargo area, so have a look under the rubbers from the inside.
Depending on the year, condition, colour scheme and the seller, anything from £300 to £2995 on some forecourts with that mileage. I was interested in this E320T (link below - sorry, haven't mastered hiding behind a word yet!) - love the colour scheme, and it has sportline, but thought it was too pricey for the mileage. A rare example though, so the priced reflected that.