Okay, this may be a stretch for some folks, and even if it's not your bag, I implore you to just consider the possibilities of just how many items in the store we consider to be 'too difficult to make at home' that are actually quite easy.
4 cups milk (your choice of fat quantity or type)
2 tablespoons yogurt or a package of yogurt starter
Scald milk (185 degreees if you have a thermometer, if not, it's that point where the milk is steaming but not boiling). Remove pan from hot burner and allow to cool to 110. Add starter or 2 tablespoons of commercial yogurt (this is where you get your good bacteria from). Keep at a constant temperature between 90-110 degrees for about 4 hours, or until the yogurt firms. I do this with a crock pot. Turn it on the warm setting for a few minutes (maybe 10 - depending on the type of crock pot you have) and then back off for 45min to an hour or so).
Yes, this is something that has to be watched - no that you have to be right on top of it, but you may not want to make it on the day you're going to Sam's Club, pick a rainy day when you're going to be home anyway to give it a try.
Why the commercial yogurt? Commercial yogurt has the good bacteria already bred in it, and it's easier to find than yogurt starter, unless you have a plethera of health food stores around.
I sweeten mine with homemade strawberry jam, or with honey and I add homemade granola for heartiness.
If you want to flavor and sweeten prior to setting, add those ingredients at the very beginning.
****I'm adding this addendum after an excellent reader question.
Okay, after the four hour curing period, it should be the firmness of commercial yogurt. If it's a little thin, don't worry, you can leave it to cure for up to 7-8 hours. Lowfat milk takes a little longer to set than whole. After it has set you just refrigerate and eat in within a couple of weeks.
You can also either put it in cups as a liquid and cure in the cups in a warm water bath, or you can just cure the whole batch and separate into cups later. I personally put it into cups first. Since you are not using high heat during the curing process, Rubbermaid or like style containers will do just fine. If you wash an reuse butter, cool-whip and other such containers, they work fine too. I've tried them all!
Also, the yogurt will thicken just a bit more once it gets cold in the fridge.As I side note, this is what I usually do with older milk - not spoiled milk, but the milk that has a few days on it and I want to start a fresh gallon for drinking. The scalding process kills off bad bacteria, but it won't work on milk that has already spoiled.This is also a good thing to do with your leftover milk if you're going out of town for a few days and don't want to waste your milk!