I use to have a recipe to make home made yogurt just using a glass jar and heating the milk to a certaint temperature. Of course a yogurt maker would be easier. If I can find the recipe I will post it on here or send it to you.
I do remember though that you don't have to buy yogurt starter at a health food store or anything like that. You just put in a couple spoonfuls of any kind of plain yogurt that you get at any store and the live cultures in it will multiply. Then once you make one batch I believe that you can use that a few spoonfuls of it to make the next batch.
I hope this helps.