When you are doing freezer cooking there are several containers you can use. Here are some of the options.
1- Ziploc freezer bags are probably the easiest to use and fairly inexpensive
2- Freezer containers with lids can be purchased as well. I know walmart sells all shapes and sizes.
3- Glass baking dishes can be used as well .But you can't take these from freezer to oven. They need to be defrosted first.
Make sure you also have some masking tape and a permanent marker so you can label your meals.