I don’t know where you are living, so the Las Vegas NV prices probably wouldn’t be relevant for your area. You can find out, however, by contacting businesses that supply helium gas (for balloons), because they will know where you can buy nitrogen gas, if they don’t carry it themselves. Certain tire dealers are now filling tires with nitrogen gas only, because the oxygen in the air we breathe isn’t good for tires, as it leads to the deterioration of the tires, by a process known as Oxidation. Also, any welding shop near you will carry tanks of nitrogen for use in their welding operations, so they would know where it is being sold in your area, and how much it costs. Hope the above information is helpful to you, and make sure that you specify (when ordering some) that you do NOT want LIQUID nitrogen; only the gaseous kind.