The city center used to be beautiful, with parks, squares and monuments, surrounded by old buildings. The war has taken its toll on the area, but there is a marketplace where people come to barter. We might be able to get the stuff we need, provided we have something to trade.
If you're lucky enough to gain access to Central Square, make sure you take advantage of it. This goes double if you have Katia in your group. Central Square has 4 merchants. Each one has a different selection of items to offer.
Materials Merchant: Always has Components and Wood. Sometimes has Parts, Weapon Parts, Broken Guns/Armor, and Fuel. Rarely has Jewelery. Wants Moonshine, Bandages, or Medicine.
Luxury Merchant: Carries all the 'indulgence' items, including Moonshine, Cigarettes, and Coffee. Wants Jewelery, Bandages, and Medicine.
Medicine Merchant: Has Bandages, Medicine, and High Quality Alcohol. Wants Moonshine.
Food Merchant: Always has Raw Food and Water. Usually has Vegetables and Canned Food. Sometimes has Sugar. Wants Moonshine, Bandages, and Medicine.
NOTE: The strategy below may be considered an exploit, as it can provide you with an almost infinite supply of items. Use at your own discretion. DOES NOT SEEMS TO WORK AS OF LATE.
If you look at the merchants, you should notice that they all want something that is sold by another merchant. This means you really only need to bring a single high-value item (Moonshine is a great one) to get a commerce engine going:
1) Trade Moonshine to the Medicine Merchant for 3 Bandages and 3 Medicine.
2) Trade a Bandage to the Luxury Merchant for 10 Cigarettes, 10 Coffee, and 2-3 Moonshine.
3) Trade a Medicine to the Materials Merchant for as many Components and Wood as you can carry.
4) Trade a Moonshine to the Food Merchant for whatever food you want.
6) Return the next night. Pick up the moonshine you left in the park. Repeat steps 1-6.
There is a guy living in the apartment on the left side of the building, he will occasionally come out for a smoke. He will also lock all doors behind him after passing them and warn you if you trespass inside the building or get too close to him. You can open these doors with lockpick/crowbar but you have to do that again if he locks the same door after it's been opened previously. He is armed with an assault rifle and will shoot if you are seen in the apartment for some time. Going into the sewers doesn't count as trespassing and there are several piles of rubble you must dig through before reaching some supplies. Killing or mortally wounding the guy living in the apartment will mark you as a bandit. An armed NPCs wandering outside the apartment will attack/ shoot you on sight the next time you visit. If you kill someone on the second visit and escape successfully, on the third visit, some armed NPCs shall wait you upon the entrance. From my personal experience, the Central Square is the hardest (maybe impossible) location to completely sweep out (even in comparison with the Military Outpost or the Ruined Villa with deserters) since the armed NPCs moving in a group and there is no place to hide. 1 gun in duel with 3 gun stands no chance to win.