Right now, the most expensive single-day park hopper ticket is 244. That said, anyone buying single-day park hopper tickets is making an absolutely ridiculous choice. Not possible to see enough in both parks in one day to justify that expense. Admission to just Disneyland on a summer weekend day is $179, less on a weekday, and less still outside of peak season. Point is, saying that a day pass to Disney is way more than $270 is, as I said, simply not true.
And I've gone in December; it was pretty freaking awesome.