That price is terrible to take a chance for.
I have purchased fake cases from Amazon even with Amazon as the seller.
Amazon is easy to get a refund with though.
The ATT website discounts Speck cases pretty regularly. Amazon with Amazon as the seller is worth a try.
You can also go to Best Buy. If Amazon is selling the case for a lower price, Best Buy will match the price. Amazon must be the seller though.
5C cases have been pretty heavily discounted everywhere.