Cost me $5 and holds steady at 115°. However, the right temperature setting is well below the "1" setting and required a mark of paint so that I know where to set the knob. It's designed to get MUCH hotter, but hey, it works!
The cool thing is that the hole in the lid is the perfect size for a jelly jar of gelatin.
There are many kitchen appliances that would do the same thing; like electric coffee thermoses, etc., just gotta get creative.
Congratulations. You are now a full-fledged member of the McGyver Memorial Institute.
If you are feeling really adventurous, you will now look inside the fondue pot to see if the thermostat has either a calibration adjustment or something mechanical that can be easily bent to place the 115 F point nearer the middle of the scale. It is sort of generally bad luck to operate near the low end of the scale, because of things like stick/slip friction and possible sensitivity to outside influences. Also, you could really cook your gelatin if you bumped the knob even a little bit. (Cooking your gelatin would be in this case equivalent to cooking your goose, only less tasty.)