Final answer:
The provided information is related to economic principles of opportunity sets and indifference curves rather than the specifics of an appetizer's price.
Step-by-step explanation:
The question regarding the price of "Crunchy onion rings" does not appear to be directly answerable with the information provided. The provided information discusses a scenario involving opportunity sets and indifference curves, typically concepts found in economics related to consumer choice and budget constraints.
When the price of haircuts increases to $30, Ogden moves from a higher to a lower opportunity set and indifference curve due to the price of pizza also increasing, which indicates that his budget or preferences have changed, leading him to a different consumption choice.
This scenario exemplifies the effects of price changes on consumer behavior, where an increase in the price of goods can result in a consumer moving to a less preferred set of choices due to budget limitations. However, it does not directly answer the question about the price of an appetizer. To determine the cost of the "Crunchy onion rings", one would need a menu or a price list that specifically states the price of the appetizer in question.