(PROBLEM # 1)             13-Paper JAM 
 Paper is having trouble leaving 
the main paper tray.

This is a common error in which the paper from the main sliding tray does not go into the printer fully and stops.
There is a FEED Roller in the printer which is used to feed the paper from the main paper tray.
This part does go bad after about 2 years of use (whether you've used the printer a lot or not).

ON SITE REPAIR: Labor $99 + Parts ($22 + tax)
DEPOT REPAIR: Labor $79 + Parts ($22 + tax)

(PROBLEM # 2)               13-Paper JAM 
Paper is having trouble leaving the
  MP MANUAL MULTI PURPOSE tray.

This is also a common error in which the paper from the MP "POP-DOWN" tray does not go into the printer fully and stops.
There is a FEED Roller in the printer which is used to feed the paper from the main paper tray.
This part does go bad after about 2 years of use (whether you've used the printer a lot or not).

ON SITE REPAIR: Labor $99 + Parts ($32 + tax)
DEPOT REPAIR:  Labor $79 + Parts ($32 + tax)

(PROBLEM # 3)               13-Paper JAM 
Paper gets stuck IN THE BACK and
comes out CURLED UP near bottom of page

This is a VERY COMMON problem. A few years ago, HP actually had a recall for this problem.

The problem is with the EXIT ASSEMBLY which prevents the page from coming out easily. Since the paper gets caught at the top of the exit assembly, part of the page is still inside the fuser. This lower part of the page gets CURLED from the extra time it spends in the heated fuser.

ON SITE REPAIR: Labor $99 + Parts ($44 + tax)
DEPOT REPAIR:  Labor $79 + Parts ($44 + tax)