If it is a carb motor, then you may get someone to pay up to $600 if it has relatively low miles and you guarantee it to run.
Around here some guys have been buying throttle body motors for $800, Vortec's for $900-$1000, and LS1's for $1000-$1200.
All of the prices are complete with accessories and brackets. With the fuel injected ones you get a computer and harness, but usually the harness is scrapped for an aftermarket unit without all the unnecessary transmission wiring. Some guys then opt to buy a 96 model ECM for a manual transmission because they don't use the Vehicle Anti-Theft (VATS) system or have the computer controlled transmission programming.
That may be more than you wanted to know, but hey, I've got time.