Which used Mercedes C-Class estate should I buy?
Cars with the manual gearbox will be significantly cheaper, but spend more to get an automatic if you can. They're smooth to drive (the manuals are notchy), make the foot-operated parking brake less of a hassle and will hold their value better.
We'd choose a C180K ('K' for Kompressor, meaning supercharged in German), with Classic or Classic SE trim. It offers the best value: enough performance for most needs, decent fuel economy, and it's the cheapest to buy.