There are deals to be had no matter which city or state. It varies widely from dealer to dealer and how well you negotiate the price. Most RV's are manufactured in the mid west which means destination costs will be higher in California. That could add $1000-$2000 to an RV in California.
California sales taxes range from 7.5% to 10% while Texas ranges from 6.25% to 8.25%. Which state will you call your home state and register the RV? Texas charges $45-$65 for license fees while California is based on price of RV. A $50,000 RV would cost around $400.