Paying more to save time and effort is fine once in a while, but be careful it doesn't become a default, finance author Dawn Cher says. How much does a bottle of water cost? At the supermarket, it's around S$0.60. At the provision shop downstairs, it's probably at least a dollar. But at a vending machine or the airport? The same bottle can cost you four to five times more, easily. Why do we willingly pay more in one context but not the other? This isn't a conversation about product quality.