Trade
Straggers
Trade between straggler groups is not as common as between gang members, or within the members of a hegemon. However, people still do gather for purposes of exchanging goods, mostly in dense pockets of population, such as
Central Park. In these areas, members of the straggler community can meet in small groups in order to share commodities and essential goods.
The major obstacle for free trade is, obviously, regional interference from gangs—who use force to attempt to coerce the straggler population into giving up vital resources—and hegemons, who despise the thought of stragglers attempting to gather and consolidate power, and will usually take considerable effort towards breaking up these coalitions and axises.
Another, perhaps equally large, obstacle is the lack of obvious currency. With the fallout, government-backed currencies collapsed and lost all of its value, and it is not uncommon for people to burn old pre-pandemic money for tinder. Without the financial backing of the state, the monetary system toppled. Stragglers nowadays most bicker and barter for their goods. As these trades are rarely standardized, traders often make one-time deals, or seek what they need or want. This makes it intensely difficult to establish a baseline 'value' for one asset in terms of another.
Primitive currency arose from this chaos. Some people use furs to barter with others for various goods, as nearly everyone can see the value of fur, particularly during the intensely cold winter months where it is almost impossible to keep warm. Others have gone further, attempting to feel out a standard form of currency. Some people use old jewelry; others trade with stamps; other use bottle caps. There have been many attempts, to varying levels of success, of establishing some "standard" monetary unit. Because stragglers hesitate to gather in large groups, and there are no permanent businesses, these attempts usually fail.
Some people have withdrawn from trade altogether, and have insisted upon being entirely self-sufficient within their little group. This is usually done by specialization. One particular member of the group may be an expert hunter, another could be very good at building with raw materials, a third could be very good at processing or cooking food, yet another could be good at scavenging for resources, and so on and so forth.
Occasionally, these specializations become surpluses, and the demand for trade between groups grows. However, these events are usually quick meetings and happenstance occurrences. Hegemons have authorized lethal force against groups that attempt to plan gatherings and events between other groups, and this severely impedes stragglers' ability to barter.
Overall, it's a stretch to claim that the trade industry amongst stragglers is healthy or booming, because it most certainly is not. For the most part, while interactions between nomadic groups occur, particularly in more densely populated areas, day-to-day threats and the sheer scarcity of resources means that most groups are unable to trust beyond their small circles and familial units (and even those bonds are tested). Subsequently, trade is usually rare, with desperation as the main motivation behind it when it occurs.
Street Gangs
Most of the trade amongst gangs takes place within the gang itself. These transactions are usually policed by an honor code. The gangsters are usually pretty close to each other, and are willing to lend a hand to a member in need, but they are also ruthless when they are double crossed. As such, accusations that someone conned them are taken very seriously by both the involved parties and everyone else in the gang.
Gangs, like stragglers, rarely have an established currency. They do, however, have benchmark values for goods, usually based off past-precedence. Since they are allowed to assemble, many gangsters trade with the same partners for the same goods over and over again, and they learn to keep these goods at a similar price based upon the needs of the individuals involved. This doesn't prevent them from making up prices as they go (and that usually is the case), but things are more stabilized than amongst the stragglers.
The other form of trade is with the hegemons. However, the hegemons operate with loyalty and tribute more than direct transactions. They may offer the gangs food or materials for their shelter, provided that they give them a share of the wares they received from raiding stragglers or other gangs, or an oath of loyalty and subservience. Hegemons may reward a gang for a job well done, or use goods to entice them to bend to their will once more.
Hegemons
Trade between hegemons is practically nonexistent, and could be hazardous to even attempt it. The Crimson Saber and the Golden Banner do not like each other very much, and most mediations for goods consist of a lot of death threats and shootouts. This suits them just fine, as hegemons tend to be self-sufficient for all the goods that they could need, and they prefer not coming in contact with the other hegemon. For the most part, they avoid each other and keep up the wary peace.
Trade within a hegemon, on the other hand, is very common. Hegemons, because of the relative stability of their societies, are able to develop internal currencies and markets. While bartering is still very common, the hegemons have found means of standardizing the value of certain goods. A animal hide may be worth a specific number (or number range, to be precise) of vegetable crops. Depending on the hegemon, an internal means of 'paper money' may be available. The Crimson Saber prefer to use keyrings, while the Golden Banner trades with poker cards.
Hegemon society is very capitalistic and market oriented. The means of attaining these goods are still governed by the individual and not the state, and a lazy and useless hegemon member would likely starve. Hunters and herders are able to capture and raise animals for their meat and hides. Farmers grow their crops, and can use them for foodstuffs and ointments. Ultimately, everyone within a hegemon must find a means of supporting themselves, either by generating raw goods that people can use, or offering a service that people are willing to pay for in return.