Please help me price my car! Valuable or piece of junk??

I was reading the thread about MB 1991 420 SEL cars, and
actually all of you seem very knowledgeable about this car;
perhaps one of you could help me. I currently own this
vehicle and want to sell it and I have no idea what to list it
for. Insurance companies wont even give me full coverage
because it is so old, it bluebooks pretty low prices, most
say because it is so old it is a piece of junk. Those who say
that dont know anything about MB. I dont really know
either, but isnt this car somewhat of a classic to some? At
least more valuable than 1991 vehicles made by other
manufacturers? It is white, grey leather interior, great
condition. Sunroof, interior wood panels, tinted windows.
200,000 miles. The A/C recently stopped workimg but only
because it ran out of R-12 coolant (I have looked
everywhere for that stuff, hard to find! So prob just convert
it) -What would you list this car for? Would somebody who
knows and values this type of car pay a price higher than
what I find when I price it online? Any ideas? Thank you in
advance!

BTW, I have been more than impressed with this car. It is
25 yrs old and has more power and reliability than my
newer vehicles. It is a tank! Lol