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Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why are green bell peppers so much cheaper than all the others?

Last time I was at the store, I noticed red, yellow, and orange bell peppers cost twice as much as green ones.  What's behind the price difference?
gpt
There are more green ones.

All of them start out green and only turn yellow or red when fully ripened. They’re literally the same thing.

Selling fully ripened produce is a dangerous game since the shelf life is inherently shorter, therefore stores prefer to sell less ripe produce so that they’ll keep longer and go to waste less. That’s why people buy bananas that are still green, so they’ll last several days and still be edible. 

From a farmer/wholesaler standpoint, allowing peppers to ripen is a waste of time and resources and introduces numerous variables that could end up costing money. So only a small amount of them are allowed to fully ripen, and then those cost extra due to their scarcity.