Coles is currently selling the Optus $30 SIM pack for $10 in-store. This deal ends at the end of Tuesday.
I know you only said you were looking for the $30 SIM pack, but I will also note that BIG W is currently selling the $40 SIM pack for $15 in-store. This deal ends at the end of Wednesday. (Optus is also selling this on their website for $15 too.)
Interestingly, Officeworks have price-matched BIG W and Optus for the $40 SIM pack, but not Coles' deal on the $30 SIM pack. That means you should be able to get Officeworks to price-beat Coles and get the $30 SIM pack for $9.50 at Officeworks.
I cannot find any Optus SIM packs on discount at Woolworths, Target or Australia Post. I don't recall seeing Kmart selling SIM packs at a discount in the last few years…
Coles is currently selling the Optus $30 SIM pack for $10 in-store. This deal ends at the end of Tuesday.
I know you only said you were looking for the $30 SIM pack, but I will also note that BIG W is currently selling the $40 SIM pack for $15 in-store. This deal ends at the end of Wednesday. (Optus is also selling this on their website for $15 too.)
Interestingly, Officeworks have price-matched BIG W and Optus for the $40 SIM pack, but not Coles' deal on the $30 SIM pack. That means you should be able to get Officeworks to price-beat Coles and get the $30 SIM pack for $9.50 at Officeworks.
I cannot find any Optus SIM packs on discount at Woolworths, Target or Australia Post. I don't recall seeing Kmart selling SIM packs at a discount in the last few years…