Exact instruction:
1. Go to Items -> Custom Attributes in backend.
2. Click + New Product Attribute
3. Fill surcharge_price_override as attribute code, 'Bottle deposit price' as attribute name
4. Set Custom attribute type as Floating point number and Frontend input type as Text.
5. Save it
Now if you go and edit any product, you will be able to enter the value for a field named 'Bottle deposit price'. The system will take that value instead of the default price of the deposit product.