The fact that you can sell garbage, you will learn at the very beginning. However, it will not be clear to whom and where. Each major settlement has several merchants. You can only sell weapons and clothing to a gunsmith or clothing vendor, respectively. They don't buy garbage. However, there is a general goods vendor in the city. It is marked with a "cash register" icon. Approach him, examine the list of goods and hold G to sell all the garbage.
Hurry up to get working codes for free sets with lots of free parts, weapons, a new armored car and other prizes.
The studio has acknowledged several failures in the past.
The project is multiplayer and free.