Here's a lens you don't hear too much about; The Miranda 24mm f/2.8 MC Macro. This is a manual focus, auto-aperture ("A" type) prime, about the same size and weight as a Pentax M or A series. It takes a 52mm filter.
Apparently this lens was manufactured by Cosina for the Dixon Retail company, after they took over the Miranda brand in the early 1980's.
I've found that it produces sharp and clean photos, with vibrant colors and good contrast. Not much visible distortion and above f/4.5 the edges are reasonably sharp.
I paid $90.00 USD on eBay, from a U.K. seller, and believe it is a good deal. It seems as good, if not better than my Sigma Super-wide 24mm.
It is especially good for scenics and walk-around shooting. It does benefit from a (generic) WA hood to reduce flare and improve contrast.
Overall, a fine WA for less than $100!
Ron