Answer:
For the free trade, the most important benefits are for the merchant and for buyer or consumer. Because, first, for the free trade is not necessary pay for a place to work, so, second, the service or the product is cheapest as in the other places for the buyer.
The two costs are, in one hand the difficulty of being knowing, to sell the service or product, because it's in a free way. And in the other hand, the other cost is to start independently.