Mac Air Value

I am upgrading to the newest Mac Air and will be selling my old one. I am trying to determine what would be a fair asking price. It was purchased in April, 2012 and has the following:
Hard Drive - 128G
Memory: 4 GB
Processor Name: Intel Core i5
Processor Speed: 1.6 GHz
Number of Processors: 1
Total Number of Cores: 2
L2 Cache (per Core): 256 KB
L3 Cache: 3 MB

Any input would be appreciated….Thanks

Checking e-Bay for similar models is probably your best indicator of its value.

- Nick