The economics of renewable energy sources are very important factors to encourage its use in the short and long run. The most important economic factor is associated with the initial investment cost of renewable energy systems. Despite their significance, operational costs do not primarily drive the decision to adopt specific renewable energy systems. The objective of this review is to investigate the economics of renewable energy systems in the agricultural sector concerning the initiative investment cost, the operational cost, and the economic returns of these systems. The results showed that the initiative investment cost in the solar energy systems was the cheapest compared to the systems. This fact contributed to the high distribution of these systems in agricultural activities. The operational cost of the other systems including the wind, geothermal, and bioenergy systems were lower than the solar energy system, but still, their use in agricultural activities was for specific purposes. The economic returns of various renewable energy systems depend on their intended use and the nature of agricultural activities.