Check out CarPats.com
, you can find some used engines starting around $2,700. Hard to say what condition they are in unless you can see if they can do a compression test.
Otherwise, with rebuilding the motor, at least you know what's going to be done and the condition it's going to be in. You should be able to have the motor rebuilt for less than $3,500. Labor, shortblock, gaskets, heads refinished.