Easiest and least expensive are a little different, so I'll talk briefly about both.

The easiest is to go on Etsy and search for Meshtastic. You will find plenty of people who will build you a ready-to-go unit, both individual radios and solar-powered repeaters. (If you plan to put your repeater somewhere with power you can use any radio as a repeater, just put a good antenna on it.) Pre-built units start at around $60 and can go up into the hundreds, but $60 to $90 will get you a great personal radio.

The least expensive is to order a kit from one of the many companies that sell them. If the kit does not come with a case, check Etsy for cases that match your kit. Most kits do not require soldering, you just have to plug in various cables and connectors, then fit everything into the case. Some actually come fully assembled. This approach generally costs somewhere between half and two-thirds of what a pre-built setup will run. Kits start as low as $10, although most or $20 to $40, and cases are mostly $20 to $35.

One of the harder parts is to figure out which radio kit you want, but there are just two major types. Those built around the ESP32 processor tend to be a little less expensive and offer the option of WiFi, but they have a much shorter battery life. Those built around the nRF52 processor cost a little more, do not offer WiFi, but have nearly 10 times the battery life. WiFi is only used in a few specific cases, usually by repeaters and not personal units, so you may well not need it. Battery life is not usually an issue for personal radios, since nearly all of them will go for a full day between charges, but sometimes you may want more than that. Stand-alone repeaters that run off solar panels are almost all based on the nRF52 because of the battery life.

The most common starter radios are based on the Heltec V3 kit, which is based on the ESP32. It has been around a long time, it is relatively inexpensive, and it can do pretty much everything. The only downside is battery life, which may or may not matter to you. Unless that's a concern, you can't go wrong with a V3. My personal favorite is the T114 kit, also from Heltec, which is based on the nRF52. It is much like the V3, but without WiFi and with much better battery life.

I would wait until you've played with a personal radio before buying a repeater. Every Meshtastic radio acts as a repeater, so you don't necessarily need a dedicated repeated. Find out how many nodes are in your area and what kind of coverage you get. If there aren't many nodes, or distance is limited, you can consider a dedicated repeater.

Basically, a repeater is just a node with a good location that's put in a good location, up as high as possible. Because Meshtastic radios use very little power, it is practical to make completely self-sufficient solar repeater units that never require charging. You can put one of those on your roof, up in a tree, or on top of a nearby hill or mountain, without having to worry about regularly climbing back up there.

I strongly recommend that you go to meshtastic.org and read through the Getting Started documentation. It provides a lot more detail (and less personal opinion). And check out the Meshtastic communities on Lemmy. Have fun!

Theoretically you can get 50 ish miles or more with line of sight. In practice, you can get around 10 ish with repeaters. With around 30 devices, our city has effective coverage.

You also have options to use MQTT if you want to make sure a message gets through. But that requires an internet connection.

Additionally is there a way to search what's already out there without a device?

I'm running about 1w per device ATM.

So yeah it sips energy. There's a lot of nodes in the mountains that are solar powered. They work.

Very low and yes. They work great for IoT, as long as it’s not mission critical stuff as messages can get dropped or arrive out of order sometimes. But for something like monitoring a remote sensor station that’s within the Lora range, without needing a cellular plan, yes.

Its biggest + in my book is that you don't have to be a ham to make it work. There are better systems if you want more reliable communications. But its a fun side hobby and, in the event of a power outage, a decent little communicator. Although from personal experience, most of the devices piggy back of your existing cell phones and bluetooth. So ironically as long as the cell towers aren't blown to hell, your still fine either way.

In theory the protocol can support those formats. With meshtastic it's only designed for text. You can get some really basic emojis though since they are Unicode.

Yeah, we had to make a weather app on longfast to fill the void. Tech people tend to not talk all that much. We are the strange ones ;)

Most of the weather app was made from a reddit post back a year or so ago. I have no idea where though. App is a python script here if your interested.

The phone app gives the location of nodes want you to know. And most don't care. For example, in my city there is currently 24 online nodes my window node has interacted with. And 174 in total nodes it's contacted today.

It can be spotty during certain times of the day.