Mcintosh value

low-teens of hundreds$ for all three units.
since it's mint, than each unit runs at about $500ish.
all you have to do is to find it on ebay as sold listing (one of the check-boxes on left portion of ebay searsch result page and you'll see all the statistics you need for all of your units as they're still pretty popular among the vintage electronics users.

Go to http://www.mcintoshaudio.com

This web site show the asking price for the MR-77 tuner, C-26 pre amp, MC 2105 units you are asking about. These are retail asking prices for this retailer. As noted above, www.Audioclassics.com is another good source for pricing information.

Go to http://www.soundoffers.com/search/?q=mcintosh

The Sound Offers web site above lists several McIntosh products for sale including the asking price. I hope this helps.

Thanks, the references helped alot.