This is a BIG one. Particularly since in my area they will not recycle yogurt containers. And yogurt is pretty expensive, considering what you get. Making your own takes some getting used to, but is certainly worth it. Here is a recipe that we started with, which now we have modified. But I'll leave the modifications up to you. Oh, and if you have a wonder box, it is much easier than using the oven. Then you don't have to wrap it, just warm it up and stick it in there!
Here is an approximate recipe:
3 c. water
1 1/2 c. dry milk
1/2 can evaporated milk
2 T. yogurt with live cultures
Optional: heavy whipping cream (helps it with creaminess)
Optional: honey or sugar (can also be added afterwards)
Blend together, put in stainless steel bowl or canning jars, and wrap with an old towel. Heat oven to 275, put the yogurt in the oven and turn it off. Check in 8 hours, and if it is not set, repeat the process. (This is where a wonder box is really useful as we don't ever have to repeat.) Be sure to save a little of your yogurt to start your next batch with!
Pros: No little plastic cups to dispose of, and very inexpensive to make. The taste is better, too, once you get used to it (much less sugar!)
Cons: Certainly it is not as convenient or as portable. It takes some practice to figure out what works to get it heated to the right temp.