Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Amazingly expensive for two pieces of cardboard

Twelve dollars for two flimsy pieces of cardboard is outrageously expensive. Adorama/Delta would still make a handsome profit if they sold twelve cards for the same price. If you use your gray card frequently, as I do, it won't last long, especially if it gets wet. If you get a smudge on it, you won't be able to clean it without damaging the surface.