What sort of heating?

We're looking to move to another rented house - supposedly slightly cheaper as I'll be a student and closer to my college. There seems to be a vast difference in the types of heating offered in some of the rented houses. Can someone tell me what is theoretically cheaper - oil, gas or electric central heating. The current house that we're in is on storage heaters which annoy us immensely, but we'd like to be in a knowledgable position when we look round these houses?

Thanks.