1.8's are the base engine in all Chevrolet Sonics and the Cruze LS in the U.S.
You really do want a complete engine so there is a minimum of parts exchanging. I would think the 1.8's would be plentiful based on the usage in the Sonic as well as the fact few ever fail.
Just gotta find that hungry wrecking yard, although I agree $1500.00 is leaning towards the high side.
Don't be afraid to make a offer......wrecking yard prices are highly negotiable.......look at e bay as well.