My daughter buys discounted tickets on craigs list. She has done this several times.
If you want to save money on food, buy your food at grocery stores, including hot foods like rotisserie chicken (cheapest at Sams), fried chicken, and the dollar menus at any fast food restaurant. Buy your sodas in cans at grocery stores too. One 12 ounce can will fill a 40 oz cup full of ice at a fast food restaurant.
BTW, the Sea World Luau was the best we've been to, including those we went to in Hawaii. In Hawaii, the best was the one put on by the Polynesian Cultural Center.
Hope you have a wonderful time. Good luck to you and yours.