when it comes to distribution, what is the least expensive route when getting the product from manufacturer or farmer to the ultimate consumer

The least expensive route is to use "Direct distribution Channel"

Explanation:

There are two modes where a manufacturer or farmer can reach the product to the customer.

1. Direct channel: This enables the customer to directly buy from the manufacturers.

Example: Online purchase. In this the customer has direct access to the product and orders online. The manufacture has to find a source to deliver the goods to the customer.

Manufacturer should have warehouses, shipping centers, etc to deliver the product.

2. Indirect channel: Relies mainly on intermediaries to perform product distribution to the customers. This includes dealer, sub-dealer and many other to reach the product to the customer.