If you're going to Orange County, here's the list I put together after living here for a decade

Cheaper/Budget Friendly-

Bike the Balboa Pier to Huntington Beach
See a band at the Garden Amp or the Observatory
Hike the Pacific Ridge Trailhead down to Crystal Cove
Anaheim Packing District
Learn to Surf at Doheny State Beach or Newport Beach Pier
Kayak the back bay in Newport Beach
Shop Downtown San Clemente
Laguna Beach Main Beach
Crescent Bay Beach, a good cove beach in Laguna
Shaw’s Cove, another good cove beach in Laguna Beach.
San Clemente Pier, there are a lot of nice shops on Avenida Del Mar
Huntington beach Main Street and Pier, lots of shops, outdoor market on the weekends
Green Cheek Brewery Costa Mesa, do a brewery crawl to the 5 breweries on that street
Food: Chan Chan, Sup Noodle Bar, Pizzeria Fuoco, Wursthaus, Pizza Port, In and Out, Mitsuwa Market Costa Mesa Food Court, HiroNori

Pricey-

Disneyworld
Knotts Berry Farm
Hive and Honey rooftop bar
Take the ferry to Catalina Island
Food: All that BBQ, Tsurhashi, Manpuku,Nep Side Door, Houston's, Haidilao, Kaori Sushi Fullerton