Limited Resources is a written note found in Dishonored 2.
It's not what you're used to, living in a palace, but this is all the coin I could scrape up. Anton and I operated on a tight budget, and guess what, now you do too. If it's not beneath you, pick up whatever valuables you find along your way. We'll need ammo and resources to take down the people behind the Coup.
Hidden all over the city, there are underground black market shops. Look for a symbol depicting two hands, which means there's a shop nearby. Follow the signs, they'll guide you. Buying from the black market is against the law, but it could make the difference against the Duke's military. Sokolov was working on this crossbow as a gift for you. If you need it modified, those shops can help with that as well.