Guilders and US dollars are at a totally fixed rate, no advantage to pay in guilders, no reason to obtain guilders at all. The Carrefour at Cupecoy is much smaller than the one by Mark's, so doesn't have nearly the selection as the one by Mark's. Supposedly all the Carrefours have the same price for the same items. In general, Super U has the lowest prices on the island for most everything, but basically no US products, if you want those.