Honestly if you want to take the time just buying from shady and selling to other vendors can make a ton of money (relative to a level 1). Especially if you log on at certain times where there's a bunch of stuff just sitting on the shady vendor.
I like that there is some of these obscure ways to make a bunch of money without needing to do combat by doing something a bit tedious instead. You're right it almost does feel like an exploit but I know they set up the shady vendor thing that way on purpose. It's possible in this case it wasn't intended, but who knows? I mean, not a lot of people can even do extractions at all anyway, so nice perk for those that can! And you still need other players to sell the the sacs to the cooks, so just like with the shady vendor thing, eventually your supply of easy money will run out and you'll need to wait for other players to build it back up again.
I know of one or two quest turn-ins that hardly anyone seems to know about where you can buy items off a vendor and turn them in to the quest NPC for both xp and profit. I discovered them myself from just exploring town. I get excited when I see someone who obviously didn't know about the quest sold a bunch of these items to a vendor so I can snap them up and make easy money! If I'm super lucky they might even have sold them to the shady merchant instead of the regular one, for even more profit!
I'm betting there's other things like that all around that I haven't found yet, where most people don't realize they exist because they are too busy just beelining for XP gains over everything else. I'm sure before long though all these will be well documented on wiki's so it will be rare to find them just sitting on vendors once that happens.
