Hi,
I have read your proposal and it pretty easy as you wrote i.e, interfacing sim800 and make message or call. And i can complete it for you in that budget. But as per your description, if the complexity of project increases, my bid also raise. But as per your description its OK for me. i need here fair and and simple in front of you. I have completed many such type of project and i will show you some of my works if you want.