Cascade Complete Powder Dishwasher Detergent, Fresh Scent, 75 oz, White

Who pays this much for this stuff? It's only $6.00 at Walmart.

Can you explain why the 75oz size of Cascade is $0.08 per oz ($5.97), and the 125 oz size of the same product is $0.20 per oz ($24.99)?

Is this the same product that is sold at Walmart and Target for half the price ?

is this safe for silver plated flatware?