Hmmm...I did a bunch of research this past fall.
I picked up a 14 foot aluminum, in good condition...solid transom, removable fishing seats, carpeted, minimum dents, rod holders, fishfinder.
Motor I got was a 1983 Merc 18hp 2 stroke. Started up right away when driveway tested.
Bought both for $1,300.
Does your friend's come with a trailer?
For boat and motor, I wouldn't go more than $400. For a trailer in good shape add $300.