The Apex was probably toward the upper end of DB's MTB lineup. From Bikepedia the '93 Apex retailed for $715 and the had Shimano LX. The Deore DX would put it late 80's/early 90's. I personally have sold even mid-level rigid MTBs a number of times fairly easily in the $120-170 range. But, mine are completely overhauled and have not been sitting unused for years. If it needs work it might be an okay buy unless you need to pay someone else to do the work. If it needs a lot of work (tires, tubes, good cleaning, cables, pads, full tune up, etc) it is not worth anything close to the $150 asking price. But, like others have said offer less.