I really like this Viltrox AF 28mm f/4.5. Think about it, there's really nothing else like this on the market right now. It's ultra compact, it's lightweight, it's 60 grams, it has autofocus, has decent optical performance, and it's only $99.
[T]hese cameras [...] are still very competitive with any camera that's out there with the build quality the ergonomics and the lens selection you can really grow with this system as well.