In metric: 1488.35 grams.
Smith's website is very slow, very buggy, and very badly designed but I use it because Smith's is cheap. And sometimes they screw up. This is their biggest fuckup that I found yet.
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Edit
To be clear - the price is supposed to be ~$9.99.
it seems you didn't clip it (because why would you) so the sale price is totally unrelated to the coupon
I dont think it's a mistake per se, the item just happens to have a 75% off sale right now. the coupon is a worse deal but it's probably available over a longer timeframe