Planning to get minimicrophone for ipod

[MAGNeT]

I am planning to get mini microphone for ipod.But i am confuse.

Same stuff ,same person selling 3 listings on ebay and ll at different price.

Mini Microphone for iPhone 3G/iPod/touch/classic | eBay

Mini Microphone for iPhone 3G/iPod/Touch/Classic (Red) | eBay

Black Mini Microphone for iPhone 3G 3GS iPod touch 1st | eBay
How much does it exactly cost?

Also is this one worth buying?