I saw someone post one of these on reddit years ago and finally started my own at the beginning of the year. This thing was extremely simple and cheap to set up.
2 gallon cookie jar - $15 (Target)
38par led bulb -$25 (Amazon)
50 watt heater - $10 (Amazon)
50GPH pump - $10 (Amazon)
Few pounds of wet rock - $10 (LFS)
Aragonite sand - $15 (LFS)
2 gallons of water from my LFS display tank.
The tank cycled really fast. It only took like 2/3 weeks. I added a CUC of 5 hermits and a snail. I have a small banded serpent starfish that was a hitchhiker.
So far I've got zoas, GSP, a muchroom, a ricordea mushroom, monitpora, a chalice, a flower anemone, and two pavonas. Once a week I feed Polyplabs polyp booster and reef roids then do a 100% water change a few hours later.