Telstra is giving away new smartphones for people stuck with devices that lack 3G 850mhz on Telstra prepaid.
In March 2019, Telstra is refarming the 2100mhz band to 4G. Hence, if your phone is outdated enough, Telstra will give you a new Essential Plus and SIM for free.
Many Optus and Vodafone locked phones are 2100mhz/900mhz 3G only, so it might pay off to put your Telstra SIM into that and see if it triggers the offer. Telstra's website seems to be smart enough realise I have a Nokia 8 with 3G 850mhz, so no freebie for me :(.
Edit: I got a shipping confirmation email from Telstra despite not having an eligible phone, thanks to realfancyman's hack (see below)
I have a Pre-Paid service: Please complete the web form here so we have your most current details. A care pack will be posted to you within 14 days, otherwise you can call 1800 112 722 (available 24 hours a day, 7 days a week), or visit a Telstra store to find suitable replacements.
What is the device included in the care pack?
A 4G capable Telstra Essential plus Smartphone will be provided
Thank you. Your order has been submitted.