@Will X I think you are looking to create an instance of custom search that is offered under cognitive services instead of bing. The cognitive services instance of custom search is currently not recommended as support for the same for new resources is not available. Existing support for search instances of bing created under cognitive services will end later this year in October 2023. The pricing you are seeing is detailed here and it is not recommended to use the same.
I would recommend you to create a bing image search resource or a bing search resource that is available in Azure portal when you search for bing. This can help you search images from web without setting up any custom configuration.
If you want to create a custom search instance you will have to choose the first option and setup your custom search view or config and then publish it to start using the same with API. It can also search for images in your custom view as documented here.
The pricing for this instance is documented here and you can choose the tier that works best for you.
I hope this helps!!
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