You can buy pure nicotine from various sources, including online suppliers, specialty chemical stores, and pharmaceutical suppliers. It's essential 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 pure nicotine in your region, as it may be subject to certain legal requirements. Always handle pure nicotine with extreme caution, as it is highly toxic, and follow all safety guidelines and regulations when purchasing and using this compound.