I want to buy the arduino gsm shield but it will cost me over $100 USD. Ouch. I am seeing others for around half that price but I don't know if they are any good. I want to use the bluevia service with this. Anybody recommend a good gsm shield for around $50? LinkSprite maybe?
you can try this one: http://www.seeedstudio.com/wiki/GPRS_Shield_V1.0
It is cheaper. I purchased it from ebay for around $45
What service do you use with it. I want to use bluevia and I want to make sure that shield will work with that and I can get everything up and running smoothly. Are there any simple tutorials for that shield?
get the SM5100B from sparkfun
Is that just the module or does it come with that sim holder and everything and a sim card? Because I need all of that.
Before buying any GPRS/GSM shield you should check the bandwith in wich it works. For example I bought this one:
and in specifications it shows this
works on frequencies EGSM 900MHz/DCS 1800MHz and GSM850 MHz/PCS 1900MHz.
Im from Argentina, and I know that the 3 cellphone companies here work on tohse bandwith so I wont have any troubles working with any of them.
Most of this shield do not come with a SIM card, because that depends on your country companies. Im not sure, but i doubt they do.
As for the comunication, there are plenty of libraries, not sure they work. I connect by serial and use ATcomands (probably you should read about that too, about the limitations and if its compatible with your project). Anyways, im not sure if I answered your question. But as long as the shield bandwith is compatible with the companies on your country, I dont see any obstacle on getting a cheap one over the expensive one (besides some features the expensive one may have).