I'm afraid I can't offer specific info - you didn't mention which shuttle service gave you that quote. It sounds fairly high to me. In case this is the company, here's one URL to check out:
Last time I read any discussions, it was $35 one way for a van from LGB to San Pedro. You'd need two each way, most likely, (unless you pack awfully light).
Hopefully, you'll get some info from others.