You can't make beer, wine or cider just from demarara sugar. You could make a malt-based beer and add up to, say 15-20 of the fermentables as sugar, but it would dominate the flavour and might be best suited to a stout. I understand that in the Caribbean, sugars like this are used to make a wash as a precursor of rum, but by the time you've gone though the formalities of getting a licence to make rum you'd be better off buying a case or two of Captain Morgan.
Flog it round the neighbourhood in the autumn to little old ladies who want to make Christmas cakes and then use the proceeds to buy a bag of malt (and a bottle of rum).