Tangentially related: I set up a security camera based on Raspberry Pi in an area with no wifi. It sends notifications and pictures to my phone when any motion is detected. From T-Mobile, the hotspot was free and the data plan is $5 a month. The data plan only has a few hundred meg of "fast" data but unlimited 128k/sec after that. Which is perfectly fine since the images it sends are usually around 100k each. It's been working great for months.
A rare trifecta of cheap, easy, and good. (Although it did take a weekend to build and test.)
A rare trifecta of cheap, easy, and good. (Although it did take a weekend to build and test.)