Its 10Gb for prepaid (and I suggest you remove your number from this public forum)
All you need to do is recharge before the end of this month for $40 or more.
The Prepaid bonus data is available on $40+ recharges on all eligible Prepaid Mobile plans or when you purchase $40+ value SIM. Customers must recharge between 01/04/2020 - 30/04/2020 to be elegible.
Eligible plans include: New Turbo Cap Plus,Optus Prepaid Supercharge, Crew Cap, Turbo Cap Bonus, Super Cap by Optus, Prepaid Mobile Broadband, Optus Prepaid Cap, My Prepaid Ultra, My Prepaid Ultra Plus, My Prepaid Ultimate, Prepaid Ultimate Plus, Optus Prepaid Epic Data, Optus Prepaid Epic Value.
Keep in mind: Additional data may take up to 72 hours to apply and does not rollover.