"Landed cost" is the total cost associated with getting something from manufacture to holding it in one's hand. On Shark Tank, when an entrepreneur mentions landed cost, they are included how much one unit of their product cost in terms of manufacturing, shipping, and any import or export duties that may apply. In a very real sense, it is the most accurate cost of a business' product that doesn't also factor in marketing.
Landed cost is also exclusive to what the product costs. Other costs the business must pay are factored into the difference between gross and net profit (if any). It also does not factor in the cost of customer acquisition.