This thread was started about 10 years ago. Many good lights became cheaper since, trickle down economy, etc. etc.
To answer the question, Niterider Swift 450 can be easily found for $22-$25 these days. I got mine for $35 earlier this year but it was prior to Swift 500 release (it took over the $35 price tag). A bunch of lower Luminas are also below $50 but I like the “self-contained” type of mount in this one. Great light.