Gas Bottles... You need a rent agreement I think (or proof of residence) and the best place to go to is the gas place behind the market in Mapusa (Barat Gas I think) and when we bought it we needed to buy a cooker with the gas bottle as the gas bottles were subsidised from the governement. We already had a cooker so we just bought a pan instead. Wasn't too expensive and took them away the same day.

Hope this helps

thanks for the info Rob