Research on alternative fuel development gains importance day by day with respect to environmental concerns and issues. Alternative fuel research can yield a revolution for spark ignition (SI) engines due to their being one of the widely used energy systems worldwide. However, most studies miss the environmental impact and economy of alternative fuels, while focusing on performance and emissions characteristics of different alternative fuels. The present paper aims to introduce a novel perspective to evaluate fuels environmentally and economically. For this purpose, exhaust emissions from an SI engine fueled with gasoline, liquefied petroleum gas (LPG), and hydrogen are evaluated at a constant engine speed of 1500 rpm and the same equivalence ratio of 1.0, using the emissions index, power emissions index, energy emissions index, environmental impact, environmental cost, and environmental and social impact cost. At the end of the study, hydrogen is found to be less harmful than other fuels based on its environmental and social impact cost. On the other hand, hydrogen has the highest environmental cost at each ignition timing compared to both LPG and gasoline, whereas gasoline has the best performance from the viewpoint of environmental costs. The current paper is expected to be beneficial in evaluating or comparing different fuels in different engine types to those interested in energy, thermal studies, and environmental sciences.