Ticking in 2001 Jeep Grand Cherokee. Mechanic right?

We have a 2001 Jeep Grand Cherokee that started ticking while in idle and gets faster while driving, almost to the point of not being able to notice it once above 65 mph (due to the ticking going so fast). We took it to a garage where the mechanic said the problem was a cracked rod bearing. My stepdad suggests it may be a broken lifter (in other words, the mechanic is wrong).
The mechanic then told us it would be over $2000 to replace the engine, but he said he would see if he could find someone who would give us at least $200 for the car if we want to sell it since we can't afford to pay for the engine to be replaced.
Does anyone have any suggestions on what is really wrong with our car and how much it would actually be worth if we sold it with a cracked rod bearing?
We would appreciate any advice!
Thanks!