I am new to Shopify and using Angular Iframe inside the Liquid template (on the Dawn theme) to add items to the cart via AJAX (using add.js). I need to pass custom product options (e.g., additional price of £2) when adding an item to the cart and ensure this extra cost is reflected in the checkout.
I have tried using a third-party app to manage the options and their prices, but due to the constraints of the basic Shopify plan (which limits the number of variants and access to custom options), I am unable to set up multiple variants or access the options and prices in a way that works with my AJAX call.
Is there any third-party app that would allow me to manage custom options and extra prices, and integrate them with the AJAX add-to-cart functionality while also reflecting the updated price during checkout?