This can be the case, especially if you pre-select a discount percentage for your visitors. For example, 1-20%.
Ama Search Bar gets results directly from the Amazon API, which isn't always "perfect" and isn't 100% synced with the Amazon site itself.
Try selecting a different category or subcategory and try leaving the discount option to the default value "any"
Article ID: 88
Category: Ama Search Bar