What are /r/microcomputing's favorite Products & Services?

From 3.5 billion Reddit comments

Something running linux and able to do usb host would be the cheapest way, then you could use a 3g dongle to do cellular. However, this probably falls down on the low power part.

After a quick look, that puts you with somewhere around the Pi a+, or https://www.olimex.com/Products/OLinuXino/iMX233/iMX233-OLinuXino-NANO/open-source-hardware, or https://www.olimex.com/Products/OLinuXino/RT5350F/RT5350F-OLinuXino/open-source-hardware

That second one looks like it has lipo charging and such, which would let you charge the battery from the panel. You might have to add something to turn it on and off, but you might be able to do with with the hardware that's already there?

Everything is a trade-off.

• If you are just doing a one-off of a few plants and already have a few PIs laying around, just use them.
• If you are thinking of making lots of these, want each one cheaper, invest the time in microcontrollers.
• If you still like the PI, but want to save a few bucks, you can get the $5/$10 Zero/ZeroW version. But they are hard to get in quantity.
• You can't beat the PI for rapid prototyping, since there is very little to learn if you know Linux and a random programming language. But with new devices, there are many ways to program it (Arduino, Lua, MicroPython), many ways to flash it (Arduino, PlatformIO.org, UF2, etc), and many RTOS choices.

So it depends if you want to make plant stuff (and spend more money), or play with microcontrollers (and save per plant). If start down the first route, you can always come back and make it cheaper.

Maybe something like this hidden under the seat? It's about the size of a pack of cards, it looks like.

EDIT: For this application, I really recommend a commercial solution, because this is one thing you absolutely do not want to go wrong when you need it. That being said, there are two types of GPS - active and passive. Passive GPS' just take down coordinates and you get them when you plug the device into a computer, so that's not what you want. The device I linked you is an Active one, so it will report location to you wirelessly through a pre-paid SIM card. Definitely the way to go.