It's cheap because noone wants to live there.
You have to connect to water, sewer, power (or build a well and septic), you still have to get it permitted and inspected, etc, etc, etc.
It's a walmart "Neighborhood Market" which looks like a grocery store to me. There's even pictures of the inside.
I'd be surprised if there are many suburban areas that are more than 5/10 miles from "stores" for some value of store. Taking some central place of Ridglea gets me a 2 mile walk to Walmart. But there are no sidewalks.
The nearest grocery stores appear to be on the other side of the highway, and like an hour's walk from inside the neighborhood. Although literally no one here is walking to Trader Joe's. Just having a Trader Joe's here kind of implies that.