Hello,
As I understand, you need to send data to thingspeak from esp8266 over GPRS.
I have worked on ESP8266 module and devkit and have good knowledge of GPRS modules and AT command sets required to configure GPRS modem. I also have working experience of various protocol viz. http, mqtt, udp which can be used for server side communication. Please visit my profile for more information about my expertise.
The scope of your requirement is not clear from your description. I will need more information for providing an accurate estimate. The current bid amount is indicative, please initiate a conversation to discuss more on the project.
Regard
Niraj