You need figures for the raw materials, that is, the potatoes, and the empty baskets, and for preparing filled baskets. This is the cost to the seller. Call this value C. The seller will buy in bulk, so the outlay at the beginning is high.
The seller sets a price for the filled baskets which the customer must pay. Until a certain number of filled baskets have been sold, we’ll call this X baskets, the seller will not be able to cover the costs. But when X baskets of fries have been sold the revenue from the sales will eventually cover the production costs.
This number X is what is meant by “will they need”. They will need to sell X baskets of fries. We can’t find X until we know how much the customer has to pay for the filled basket, and until we know how much C is, the production costs.