A couple good deals: box of filters turned out to have a bunch of those Canon lens mount converters, an original Leitz LTM>M mount perfect for my M3, an M2/M3 brass rewind crank (looks closest to what I've seen called the Magnum rewind), a VIOOH, some original Canon filters (what I was originally interested in), some other little RF bits.
Craigslist deal a couple years ago now, Canon RF listed. Show up and the guy has an <EP> VT with a beat up 50/2.8 and a VT Deluxe with a 50/1.2. He says take any combo you want of one lens and one body for $200. So, I look them both over and the Deluxe's shutter is jacked up. VT is well used but seems like it is working and the RF patch is brighter, so I choose that. Lens choice should be obvious. I didn't have cash for them all, and $200 for a broken VT-D + thrashed 50/2.8 didn't seem like such a great deal.
So, I give him the cash, and he then offers to and throws in an IVSB + FD 50/1.4 with the Canon adapter to make it fit LTM, all for another $25.
Sold the IVSB, FD50, mount converter and now my VT + 50/1.2 are better than free! 1.2 is in phenomenal shape compared to the rest of the kit, I'm not sure how he put it all together or why, but that's one of my favorites.
I've also bought an 8-element Takumar 50mm f/1.4 for $20, but that's not for RF land.