Would you ever consider buying somebody else's reloaded ammo and/or have you ever been successful at selling reloads?
I would never sell my reloads. I necksize only and consider my reloads unique to the chambers of my guns that the orginal factory rounds were fired in. (.303 Brit, .30-30, 6.5 Carcano, .38 Spl, .30 Mauser, .45 AutoRim).
As far as buying reloads, my answer is mostly NO. My basic attitude is that reloading is something an individual does on their own recognizance for personal use.
A friend of my son inheritred a nice bolt action sporter and a box of his late relative's reloads, with the recipe on a label on the box. On a range trip with my son and me, he decided to shoot the rifle with the reloads. The first gave stiff recoil. The second jammed the bolt closed. The bolt had to be opened by rapping the handle with a block of wood. The primer showed classic over pressure signs: flattened with powder smudges around the primer pocket. At home I checked the reload recipe label against my Hornady Handbook of Cartridge Reloading. The charge weight was 2 grains over the maximum charge for that cartridge, powder type, bullet weight. The relative may have been pushing the envelope with that load and never got to test it, or he may have even set it aside to break down to components to be redone but passed away before he got around to it. I informed my son's friend.
Once I did buy a couple boxes of handloaded 6.5x52mm Carcano from a frequent gun show vender who specialized in obsolete, hard-to-find ammunition (labelled 27gr IMR 3031 powder with 160 gr FMJ bullets). The casings were new so I'd call those handloads. The rounds proved to be as mild as my 6.5 Carcano reloads (Norma casings, 28gr 3031, ,264" 160gr JSP, LRP). I think that is the only reload/handload ammo I have bought.