What is the cheapest gps unit for Nikon d7000?

Hi I'm planning to buy a gps unit for ma Nikon d7000. What is the cheap n best gps unit… And wer can I buy it? Wil it b available in Singapore?

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I bought the Nikon GP-1 and I would recommend against it. I had mine out for an hour the other day and it never synced up with a satellite. And this was in open country. I suggest you look these over.
http://www.amazon.com/...10ghtxcn_b