Here is an interesting blog about making yogurt in your crockpot (about $14 - $30) and or mason jars! Personally (having had a yogurt maker in the distant past) I would go this route instead.
http://www.creativesimplelife.com/ho...n-a-crock-pot/
Lots more websites if you Google 'slow cooker yogurt recipes'.
DH and I have recently discovered the delicious taste of Greek yogurt.... I need to find out how to make that. Yummm!
https://www.google.com/search?q=gree...hrome&ie=UTF-8