Yeah, unfortunately, Sandisk cards are expensive. At Newegg there’s a bunch of 16GB Class 6 cards at the $50 price point. The Sandisk card costs $55 and is only Class 2. And like you said, retail stores are much worse with prices typically 100% more than online.
I’d pay a little more for Sandisk and a little more for instant gratification, but I’m not going to pay double.