Arthrospira platensis (A. platensis) is a rich source of proteins, vitamins and is used as a feedstock for biofuels. However, the high cost of medium used in its cultivation is a problem to increase its production. This study aimed to analyze the technical viability and compare the costs of different medium for A. platensis cultivation. Therefore, the microalgae A. platensis growth was analyzed in three different medium: M1- a standard medium Paoletti (analytical grade); M2 - a standard medium without microelements (analytical grade); and M3 – alternative medium with commercial salt, sodium bicarbonate and commercial fertilizer – double sodium and potassium nitrate (commercial grade). The inoculum was prepared in 9-day process, temperature ± 30 °C using shaker with artificial light, the initial concentration was 50 g.L-1. Biomass maximum concentration (Xmax), productivity concentration (Px), maximum specific growth rate (μmax) and the medium cost for 1kg of biomass were monitored. The comparison between different treatments was conducted using the Tukey test (p <0.05). The growth of all 3 treatments presented a standard microbial process with characteristic phases. Xmax, Px and μmax showed no significant difference between treatments. The higher cost was M1 (US$ 0.90) showing that microelements was dispensable because it produced biomass results statistically identical to the others (M2 and M3). The cost in M2 (US$ 0.77) was 14.5% lower than M1 and is approximately 38.92% higher than in M3. The cost in M3 (US$ 0.47) was the lowest one. The biggest cost in M1 and M2 was NaHCO3 (45.09%), replaced in M3 by commercial grade sodium bicarbonate. M3 represented a cost about 47,75% lower than M1 and 38.92% lower than M2 and also the other indicators showed good results. According to these data, the proposition of the M3 proved to be more profitable for Arthrospira platensis cultivation.