Seem like pretty good prices for these been using one to freeze Shepard's pie to easy cook during the week for the family, works well.
I saw a bigger variety in store, if you see the picture, but links for online are below :)
Thermoglass 1 litre reseal dish $7 usually $14
https://www.woolworths.com.au/shop/productdetails/710411/dec…
Thermostone 3 litre reseal dish $14.50 usually $29
https://www.woolworths.com.au/shop/productdetails/923909/dec…
Thermostone 1.8 litre reseal dish $11 usually $22
https://www.woolworths.com.au/shop/productdetails/923915/dec…
Thermostone 2 litre reseal round pie dish $13 usually $26
https://www.woolworths.com.au/shop/productdetails/512328/dec…
OP, do you let it come to room temp before you put it in the oven? I always use disposable foil trays when I freeze Shepard's pie.