Answer:
Christmas lights are price based shopping products
Explanation:
From the question we understand that, Beth bought as many cheapest lights as possible. This means that she places value over quantity than quality.
The above is an illustration of price based shopping products where customers (in this case, Beth) see all products (in this case, Christmas lights) as similar products, irrespective of their different qualities (after all, they all light Christmas trees).
Because of this, the customer will opt for least expensive items, leaving the more expensive items.