Using raw pointers without allocating memory

I would like to ask about my approach to using pointers raw pointers without allocating any memory using pointers. I am working on an application, that is simulating classical cashdesk. So I have a class CashDesk, which is containing vectors of Items and vector of Orders, which are classes to represent items and orders. Furthermore, I want the Order class to contain a vector, which would be a vector of pointers to Item – I don't want to store the object multiple times in different orders, because it makes no sense to me. Through the pointers in Order, I only want to be able to access properties of the class Item, there is no allocating of memory using the pointers.

Simplified code:

class CashDesk {
 vector<Item> items;
 vector<Order> orders;
}
class Order {
 vector<Item*> ItemsInOrder;
}

Class Item containing only structured data – information about the Item.

I create all objects at the level of the CashDesk class – create instance of Item when needed and push it to items vector.

I have been told that I should avoid using raw pointers unless there is no another option. The important thing is that I don't use any memory allocation using pointers – really using the pointer in terms of pointing at the object and accessing it's properties. Should I rather use something like unique_ptr, or completely different approach?

Thanks for any response.