Just spotted this in Rundle Mall, but couldn't find it in any catalogues.
These are also $5 at Officeworks, but I wouldn't expect them to price match because I can't find it anywhere online.
Since $10 is the minimum credit you need to activate an Optus SIM, it's a perfect alternative to Telstra for porting your existing number in and out again to make the most of a deal with another provider.
Edit: Just saw it in Woolies Lane Cove so might be Woolies-wide.
I believe you have a choice of three plans, the one you detailed, a $2/day one, and a 45 day expiry one.