If you've ever caught even a glimpse of the pricing signs while browsing the produce section, it's pretty likely you've noticed the big price difference between different colors of bell peppers. Why are green peppers always so much less expensive than the other colors?
No matter where you shop, there's a common theme with the pricing of bell peppers; the green variety are priced significantly lower than the red, yellow, and orange counterparts. You might argue that it's because the other colors have a more palatable and enjoyable taste (and I agree), although that's not exactly the reason.
Maturity Dictates Price
The reason green peppers sit at a lower price point is simply because they're less mature. These peppers are harvested sooner, before they're fully ripened, requiring less growing time than the other colored peppers. Yellow, orange, and red peppers use more resources since they're harvested later, making them more expensive.
This also explains why the flavor of green peppers is mildly bitter compared to sweeter yellow, orange, and red peppers. If left on the plant to grow, green peppers would eventually turn yellow-orange then red, and their bitter bite would mellow and become sweeter.
No matter what color bell pepper you buy, they all originate from the same species of plant. The underlying difference is when the pepper is harvested, which ultimately has an effect on its taste and its price.