Is this the card your talking about?:
If so, I've looked up the prices on eBay, and they range between about $20-$30 on average. These are 'Buy It Now!' prices though, I'm not counting bid prices because they are like $5 and ridiculous stuff. xD
I'm using eBay Australia, and I'm using Australian prices.
Really, you can sell it for any reasonable price as long as the receiver is happy.
Hope I helped. :)
Source: eBay Australia