I bought the Apple Watch Magnetic Charging Cable while on holiday in the UK, where it cost £25, about S$53, before tax refund, likely matching the Singapore price after the refund. It comes in two lengths, 1m and 2m.
I was meant to attend the Apple Watch media launch at Nubox Raffles City if they could reserve me a set. They never got back to me, so by the time I was in the queue, I forwent the event.
Apple officially launches the Apple Watch in Singapore, alongside Italy, Mexico, South Korea, Spain, Switzerland, and Taiwan, on 26th June 2015. It'll be sold via the Apple Online Store, authorised resellers, and Malmaison, with prices starting from S$518.