There are obligatory costs for the exchange even for Singaporeans, I believe, for basic health coverage and administrative odds and ends paid to NUS (S$120). As for cost of living, Singapore is not as expensive as it's made out to be (most times we top the charts for most expensive city because they've costed cars, and that is exorbitant in Sg for policy reasons). Restaurants are not cheap but why head there when the best food is in the hawker centres around residential neighborhoods? A meal will be under S$7 each and every time, including a can of drinks or a cup of kopi. Try all the local dishes.