Give up this project.
After discuss with our team and sub-suppliers, the minimum price must be US$80 instead of US$50. Considering air mail cost, total would be US$100. Who will pay for US$100 just or a thermometer.
But we are studying a monitor of 5 temperatures, 5 moisure, 5 water content, 5 Co2. The monitor can be connected to Internet by WIFI. also the probes are communicating with monitor wirless. This is supposed for greenhouse, and poultry farming. Estimated price is US$500 to 1000