This is always a challenging question to answer. The price difference between GMO and non-GMO varies from product to product and from one location to the next. The answer depends on what type of non-GMO product is being purchased. Most GMOs consumed are in the form of processed foods, it’s estimated that as much as 80 percent of processed foods include a GM ingredient. Let’s think of food prices like car prices. An automotive company offers a plain-Jane car at the lowest price, if the buyer wants additional features, then the price rises. Food products are similar. Food companies buy the highest quality ingredients they can for the lowest price possible, since GM crops are high yielding and high quality they food industry relies on them as standard ingredients where GMOs are available. If a company wishes to offer a non-GMO product, this is an additional feature which raises the cost, like automatic starters would be on a car.
So why is non-GMO an additional cost? There is no one answer. This can be due to fewer acres or higher costs of production, further transportation distances or costs, or perhaps a greater risk to produce. Typically, GM crops are the more efficient crops, and that means their price and costs as ingredients are less than non-GMOs. In the U.S., much of the sugar found in processed foods come from GM corn. If a food company wanted to use non-GMO sugar, there are fewer acres producing non-GM corn with lower yields, making ingredient price of the non-GMO sugar higher than GM corn sugar.
This is what makes it virtually impossible to describe in dollars or percentages, how much the price difference might be for each food. Price differences will be very specific to the product and the location.