You can purchase nicotine sulfate from various sources, including agricultural supply stores, online chemical suppliers, and specialized nicotine suppliers. It's important to ensure that you are purchasing from a reputable supplier that adheres to safety and quality standards. Additionally, be aware of any regulations or restrictions regarding the sale and use of nicotine sulfate in your region, as it may be subject to certain legal requirements. Always handle nicotine sulfate with extreme caution, as it is highly toxic, and follow all safety guidelines and regulations when purchasing and using this compound.