Motor mounts bad??

I was looking at an 07 that I was thinking about purchasing for real cheap, I first noticed that there was a bad vibration at idle and when I looked under the truck you could see what looks like the oil pan pretty much resting on the crossmember below. The bolts and the mounts looked pretty good, the bolts didn't look broke and I couldnt see any broken pieces.

Is this a common problem? What is involved in replacing them? I saw the Mopar mounts on Rockauto for about 35 dollars a side, I assume you don't need to remove the engine to replace these?? Just jack up and support the motor? Any one else ever deal with this?