Buying back items and silenced weapons and other stuff

[Ninja2dan]

It's been a while since I've played, so my answers are probably just temporary until R@S chimes in.

Something that I used to do when I was running low on limited-availability ammo was to sell the empty boxes (and sometimes near-empty) to a dealer or bartender, and then buy them back. When you buy ammo boxes they are always full, so this helped me stock up on that hard-to-find stuff. I also always kept the empty boxes to the uncommon ammo for this reason, instead of dumping them like others.

One tip that helped me often was to pile tons of unfilled magazines onto one character with a bunch of ammo, and refill every magazine I owned (and had ammo for). When that was all done, I'd go sell and rebuy the empty or low ammo boxes through a dealer. This helped ensure that I always had fully stocked magazines and spare ammo.