Nobody's asked me for ammo. Fellow shooters have their own stashes. If they're in a bind, I'd certainly share factory ammo to keep them shooting; no handloads though. I shared some 22 with a friend during the 22LR ammo draught a few years ago. It kept a buddy participating in our Bullseye league.
Asked out of the blue by an acquaintance or a random co-worker? Highly unlikely I'd sell or (sheesh!) give them ammo. Sounds a lot like "what's mine is mine and what's yours is mine too!" Pretty forward if you ask me.
A few years ago, a co-worker was getting into shooting. I took him to the club a few times, helped him get his arms around handloading. I shared targets, my equipment etc. It got to the point where he expected my generosity. He'd help himself to my paper targets, rut though my shooting bag for tools, grab my spotting scope to see his targets. All of this without asking. He even wanted me to bring specific items for him to use. This got old fast and I put a stop to it. We don't shoot together anymore. An extreme example, yes, but it shows how some folks think.
Now I'm not a stingy guy. It's a pleasure to help new shooters or old shooters in a bind. Things can get out of control when other people expect gifts. Give 'em an inch and they think they're a ruler!