I think 35mm is the cheapest out of all the ultra wides. I have a Sigma 14mm 3.5 AF lens in Nikon mount, its probably one of the most affordable. Looking at completed ebay listings, this lens ranges from $70-$350, with the majority of them ending around between $150-$200. That is pretty cheap to get into the super wide spectrum with a rectilinear lens.
Originally Posted by LiamG