How much would something like this cost?

I am completely ignorant to computers and the internet, but I am curious does anybody out there have an idea of how much it would cost to hire a software engineer to design a program that would have the function to search jobs on the internet using keywords on a automated basis? An example: If someone wants to be a teacher, he/she would use that program to type in "teacher openings" or "teacher postings" and the software would be running on a continuous basis and when there is an opening the program would alert the user via email or pop up on their computer. Thank you.

You can use Job Alerts on Indeed.com to do this, which emails you once per day if new matching jobs show up. Or if you want to be updated more than once per day, you can use RSS feeds and an RSS reader such as Google Reader.