I picked up my 2000 Grand Prix GTP parts car with 38k miles on it from an insurance auction for just shy of $1000. I bought the car for the motor, found the trans is salvageable (needs side cover, 1 sensor, and may need valve body flushed). I then sold $2-300 of parts off the car and therefore I had $700 (plus the $250 trip to pick the car up) and I had a like new engine. I then traded what was left of the car to the body shop for $500 worth of labor on my 99 SSEi.

Just found a L67 engine out of a 1999 Park Avenue Ultra with 51k miles on it for $500 in Remington, VA. It is missing the Supercharger, but to use it on a 1996 car would require some vacuum line modification, so it'* best to retain your original supercharger. I'd suggest stopping at your local dealer at the time of the swap and getting 2 $7 bottles of Supercharger oil and changing that (allen head screw on front of SC nosedrive).
The SC gasket can be bought at Auto Value or anywhere that sells FELPRO brand gaskets, and the SC gasket for UNDER $16 (Felpro gasket comes with coolant o-rings and the GM gasket doesn't so the dealer charges something like $30 for the gasket and 2 o-rings).

Stock #: 607853

Part Grade: A

Remington Auto Parts
1-800-259-1814

got my 98 gtp motor with 100k with blower for $435 and no core charge... hella good deal at the time

Call or email Ed Morad. He'* probably your best bet for a used engine.

http://stores.ebay.com/Morad-Parts-Company

depending on how you find them, they can be cheap. $1000 seems to be a good figure for mid mileage (40-80k) motors. I just missed a 165k motor/tranny/harness/ecu for $200 a month or so ago, so that might be an option if you just want to get it running.

http://cgi.ebay.com/ebaymotors/GM-3-...2417QQtcZphoto

Thanks all. This thread is really giving me a good range to shoot for. If this car is as sweet as it sounds then I may need to change my screen name to "three bonnies".