The current exchange rate AUD/THB would see you paying over the odds by applying for a 30 day extension IN Thailand as opposed to applying for a Visa IN Australia BEFORE you depart for Thailand.
Thanks for the 'heads up'. Depending on the AUD cost to obtain a Single Entry 60 day Tourist Visa (currently AUD60), it might be less expensive to enter BKK and get stamped in on 30 day Visa Free, and then apply after for an extension after I arrive in Thailand 🇹🇭