Would like a low-dollar, easy to care for "roundy" sedan...any thoughts appreciated. thanks

Jim,
What do you consider 'low dollar'? Is it going to be a show-car, occasional driver or frequent, daily driver? You should find the best condition example that you can afford.
I've recently seen some decent looking examples in the $4000-$6000 range. The cost of restoring a 'low dollar' project car could be several times these figures.
If you want a Ponton, I would recommend a 6 cyl 220S over the 4 cyl 180/190 as the 6 is smoother, peppier and more pleasent to drive in modern traffic. Keep in mind that most Pontons will be found with manual trans, manual steering and drum brakes.
Modern amenities such as power steering, disc brakes and AC weren't widely availible on Mercedes sedans until the early-mid 1960s
Hope this helps, Happy motoring,
Mark DiSilvetro in Alexandria Va.
1960 220S
1961 180b
1972 250
1972 250C

__________________
DrDKW