Naptha has been the bulk alternative of choice. Not that even name-brand lighter fuel is all that expensive considering that a pint tin lasts a very long time.

Through WW2 Zippoes were often run on any available fuel. Automotive gasoline, genuine leaded gasoline, or aviation gas was what was handy. White gas was considered better than either of those and genuine lighter fluid was considered the top-shelf stuff. I understand that gasoline, particularly the military grades that are heavy with additives, lend a disagreeable flavor. Jebus knows what those additives mixes do to a smoker's lungs but if your a smoker I suspect you may not care, even if the aftertaste has a distinct 'refinery fire' flavor.

Naptha works well.