So, Yelp had told me that Sun Fat was the place to go to buy oysters [in the Mission].
And it is true that Sun Fat has a great variety of oysters, ranging from 65 cents/each to $1.35 each.
However, Duc Loi has absolutely enormous, meaty oysters for 59 cents (and those are the only oysters they have). Not sure where they're from, and sure, I've had better oysters, but they're still delicious and an absolute steal.
This is fast becoming my go-to supermarket in San Francisco, especially for meat and fish, but for produce too. I found the same organic strawberries at Duc Loi for $2.50/lb. less than at Bi-Rite.
Sure, nothing there is exactly top-of-the-line, but it's hard to beat their combination of price and quality.