I've been looking into ignition methods. All the sites I've looked at which describe how to ignite a hybrid rocket seem to talk about a quite controlled method of ignition, so I doubt lighter fluid or black powder will be that suitable. The most commonly described method involves using something called a pyrograin, or pyrovalve. These appear to be some solid that burns steadilyin the case of the pyrovalve this releases the oxidiser when it has burnt through, but no site I have looked at yet actually says what they are. Other methods mentioned include using a very high voltage, but that only seems to work if the oxidiser is pure oxygen. This site seems to have the best info:
Looking into pyrograins, as far as I can discover they are just any piece of non inert fuel. I haven't found any exact compositions yet though.