I saw this today at Coles Toowong QLD - 5KG bag for 99 cents / 20 cents per kg.
They didn't look old or anything bad.
As a single person I had no need to buy them. I hope it helps someone.
Edit:
Looking forward to any funny comments and feedback, but please be kind as it's my 2nd deal posted.
Updated: 5kg Potatoes also 99c. Thanks RADISHYUEN.
Both have plenty of stock.
Brown Onions reg price $3.90/kg
Potatoes reg price $4.50/kg
Thanks moderators for editing my title - I appreciate it.