Make a custom field as a range - like "Price" is as default in Bigcommerce
Solution 1:
Depending on what functionality you're needing from this custom field, you may be able to use it for the 'price range'. The value type is string, so this does not accept an array of multiple values, you can see this in our API reference documentation. If you're just needing to use custom fields to render the text on a template or so, this could work, but if you're needing more functionality from it, it'd be best to use something else.