This lighting deal expired…
The new condition YI 42.5mm F1.8 Lens with Macro Mode for M43rds is currently a lightning deal for $121 with free shipping, sold by YI Technology with the order fulfilled by Amazon, so Prime members get free 2-day shipping. Offer ends 10:20pm ET or earlier if sold out.
UPDATE: the link in the first paragraph is the black color scheme, but the silver color scheme is also a lightning deal for $121 until 10:20pm ET.
UPDATE: unrelated to the YI cameras, but the lightning deal started at the same time, you can get this Mechanical Keyboard with Typewriter Keys for $51 in four different color schemes. It averages 4.6 out of 5 based on 34 customer reviews and has 20+ questions answered.