The SIM800L GSM module is the most cost effective cellular module that is currently available. The module operates at between 3.4 and 4.4V and supports quad band frequencies.
Last Minute Engineers has a great turorial on using this module and can be found here.
- Supports Quad-band: GSM850, EGSM900, DCS1800 and PCS1900
- Connect onto any global GSM network with any 2G SIM
- Make and receive voice calls using an external 8Ω speaker & electret microphone
- Send and receive SMS messages
- Send and receive GPRS data (TCP/IP, HTTP, etc.)
- Serial-based AT Command Set
- FL connectors for cell antennae
- Accepts Micro SIM Card
- SIM800L Module
- GSM Helix Antenna