Martin-ger had his very cool low cost esp_wifi_repeater project published here a while back. You can find the project here: https://github.com/martin-ger/esp_wifi_repeater Thank you Martin for publishing this.
When I first saw this I thought it was a cool idea. But I also thought it needed a better than stock antenna for esp8266 and I thought it needed a decent weatherproof housing, and I also thought, gee wouldn't it be neat if this could be solar powered. I let those ideas fester for a while and this is what I came up with.
One of the worlds favorite deceptively inexpensive WiFi antennas is the cantenna. This has been written up in enough places you should have no problems finding a good link or links to different versions of it. The deceptive part in the cantenna is that the antenna is free, assuming you eat almost anything that comes in a tin can, however, the dongle to connect it to your WiFi device is expensive. I found I could generally get a Chinese made yagi with the right connector for the same price as the dongle for a cantenna. So much for free.
However, given the petite size of the 8266, what would happen if one 3D printed a cylindrical insert that would fit in a can hand hold the built in antenna on the 8266 in more or less the focal spot. No dongle required. I started liking this idea.
Next, what if you cut both ends off another can and 3D printed a clamp that would fit over the rims of that can and the can with the 8266 in it, you could make the cantenna longer in single can increments. You could also make a block on the clamp to hold a regular tripod screw so you have a way to hold it down and aim it.
Also if you use a can that has a plastic resealable top (like play dough) you have a way to keep the weather out so it should be outdoor safe if you paint it.
Now, add one more clamp to hold another can behind the one with the 8266 and you have a compartment for some 18650's and some of those little high efficiency buck regulators you can get for 10 for under $4. If you have another resealable cap, you now have a way to get in and change the batteries if you ever need to.
And if this is the same clamp design as the first one, the hole that you used to mount the thing on the tripod faces up this time, and that gives you a place to mount a modestly sized solar array. Perhaps find a very small mppt controller for taking care of the batteries.
I can see feasting on a few cans of peaches, 3D printing 4 pieces (2 clamps, i insert for the 8266, and one insert for the battery and power supplies) and doing some trash surfing for 2 plastic resealable tops (I know I have seen products with them at the market..) and boom. For literally under $10 you have a very cool long range repeater (sans solar) that you can mesh with others. This would be slick for one day festivals etc where you want to supply WiFi over a large area. Or for pushing WiFi further back into the boonies, or even in third world countries, linking towns and villages and the like together.
Add a few bucks more and they can be (somewhat) solar powered. Probably not full time but if you read the blurb on the repeater and it has some slick ways it can be remotely turned on and off. If you use the really cheepo -01 modules you need to remove the power LED and tie gpio 16 pin on the chip to reset . Not impossible but tight soldering on the little chip pin.. As an aside it is a shame that they do not bring that pin out to a solder pad so you could access it. It would cost them nothing and make the -01's a lot more user friendly for low power sleep mode....