I am trying to track patent #20080310908. How do i find out if it was sold, to who and for how much? I have been searching for a long time and don't know where to go to find this info.
First, US 2008/0310908 is a patent application, not a patent. This is important for reasons that I touch on at the end.
The best place to check ownership is on the USPTO's assignments database. Typically, though not necessarily, patent assignments are registered pretty promptly, as the ramifications for not doing so can be dire.
By looking at US 2008/0310908 (that is, publication number = 20080310908), you can see that this was assigned from the inventors to Metcom Plastics International Inc of Canada on 20 June 2008. No further assignments are registered, so we might assume that no further assignments took place. Though there is no way to be sure.
The amount is not typically public, so there is no real way to find this out.
In any case, the current ownership is likely moot, as this application was abandoned before grant in 2012 (which can be seen at USPTO PAIR).