Alternative to low calorie spray for frying sausages?
This is going to sound strange, but the 'low calorie oil' that you're looking for is water.

What you do is you start the sausages cooking in a little bit of water (about 1 cm; 3/8").  The water will prevent the sauages from getting too hot too quickly, and the fat in them will start to render and leak out into the water.  Once the water evaporates, you're then cooking the sausages in their own fat, avoiding the need to add any additional.

The water acts as a conduit for the heat, while also moderating it, so you cook sufficiently up the side of the sausages, rather than it just being really hot where it touches the pan and  burns in those spots.