If you want to use Canon EF or EF-S lenses on Canon EOS M mirrorless cameras, the Fotodiox Pro Lens Mount Auto Adapter is on sale for $40 with free shipping at Amazon by Amazon itself. Limit up to ten units per customer. It averages 4.5 out of 5 based on 110+ customer reviews and has 35mm questions answered (sorry, I couldn’t resist!).
This is an old fashioned sale, not a Lightning Deal, so the exact expiration date is unknown as Amazon price bots change prices based on a variety of factors.