I get local milk very cheaply, so making our own yogurt saves us a BUNDLE. I can make a quart of yogurt for about a dollar, and a quart of organic yogurt costs three times that.
I have a yogurt maker that comes with eight serving cups. The yogurt gets incubated right in the cups, and then I stick them in the fridge. It's a Donvier yogurt maker.
http://www.amazon.com/Cuisipro-Donvi...1599552&sr=8-1
It is plastic, so if plastics are a problem, this is not for you.
I also have an extra set of cups so that I can make more while the first batch is still in the fridge. It comes with the thermometer to get the yogurt to the exact right temp for adding the starter.
I used a cup of commercial yogurt for the starter-- a half cup for each quart of yogurt I make.
We also often add extra cream back into the yogurt, which makes it naturally sweeter.
To sweeten, we usually add a dollop of homemade jam. DH and I like it plain with fruit, but the kids like it a bit sweeter, so a teaspoon of jam in addition to the fruit does the job.
I incubate mine a full 24 hours, because I can't tolerate lactose so well (not lactose-intolerance, but I have ulcerative colitis). The longer you incubate, the less lactose will remain, and the more tart the yogurt will be.
Chill it without stirring it once it's made.
You can also strain it to make it thicker, once it's done.