IF a camera store buys used camera equipment, expect to get no more than 20% of the MSRP. Depending upon the lens mount, it will be worth more or less. MC indicates it is has Multicoated lens elements and S may stand for Sonnar. f/3.5 is a rather slow lens and 135 mm is a popular lens size in the 1960's and early 1970's, long before zoom lenses became popular or high quality.

Here is some information on the Carl Zeiss Jena lenses

http://en.wikipedia.org/wiki/Carl_Zeiss_Jena_GmbH#Camera_lenses

Is this like the lens you have?

http://cgi.ebay.com/Carl-Zeiss-MC-Sonnar-3-5-135-Jena-DDR_W0QQitemZ320378807597QQcmdZViewItemQQptZCamera_Lenses?hash=item4a9810a52d&_trksid=p3286.c0.m14&_trkparms=65:12|66:2|39:1|72:2096|240:1318|301:1|293:1|294:50