Some friends and I are going to start swapping freezer meals soon and I'm super excited. However, for those who are old pros at this, where do you find the best "container" for meals that need to be baked? I normally use gallon size ziploc bags for crockpot meals and have used the disposable aluminum pans for things like lasagna or enchiladas here and there but they start to get a little expensive. I normally wash and reuse these but won't have that option when I"m making these to give away. Any ideas on where to get these at the best price?