Universal Studios should give you a discount when you buy tickets online.
Costco and Ralph's are good places to get a discount on Disneyland admission.
If you are a So-Cal resident, you will get a discount on both just for showing proof that you are a local.
Have you tried www.mousesavers.com? They have the inside scoop on discounts. I haven't really navigated the sight religiously but I've heard good things about it. Also, are you a California resident or do you belong to an auto club like AAA? They also offer pretty good discounts. Sorry, that's the best advice I have. I'm an AP holder... Good luck.
I know that smaller banks(credit unions) give good discounts on tickets..I got a two day park hopper for my mom for 120, when at the gate they're 140..20 bucks is better than nothing!