Sorry I missed your reply. I was actually in Miami meeting with a Palfinger dealer and have been super busy. I've been getting lots of calls from different crane dealers around the country... tons of interest in this!
Good deals can be had for both cranes mounted on a truck and unmounted used cranes. Like Glenn said, it's hard to find the perfect used crane/truck setup in the secondary market. Even finding a used crane that will work well with a grapple saw is extremely difficult. I just came across a nice 2013 PM 53 SP crane w/ jib. It has 1 function to the end of the jib, but the grapple saw requires two. A second function can be added for around $5,000 - $8,000. It took me 3 months to find a used crane that will work with a grapple saw, there just aren't many in the used market available.
Price for installation all depends on the size of the crane and your truck... it can range from $10,000 up to $40,000 or more!