Good price to go see some international men's tennis.
edit: Matches start at 7.30pm and the grounds open at 5.30pm
$85.75 includes booking fees and credit card fees.
According to the page:
Australia’s Bernard Tomic will take on defending champion Jarkko Nieminen in a thrilling first match on Ken Rosewall Arena, followed by gritty Marcel Granollers of Spain against tournament third seed Andreas Seppi of Italy.
I'm guessing this price includes the booking fee since the website says 2 for $76.90