There are a lot of unanswered questions about the Sprawl. Food, for one thing. Fuel, for another. Chlorella can be grown, Bugs raised in tiered terrariums, and Tilapia raised in clean tanks. Without the Neighborhood Watch these things get destroyed, and everyone goes hungry. There are bug farms and chickens, and dogs. People grow some crops out of stubborn, poisoned soil. There are drugs like Chill.
Most tech you find the in the Sprawl is salvaged from The Dumps. Some is bought by people who have wage. How do you get wage in the Sprawl? First you need a wagespace. Usually managed by the computer network SID. Maybe its art, maybe its begging, maybe its a scam. Maybe its drugs that are wilder than what the corps will sell (wrecking another corp's property isn't cool). Some people provide specialized services. Exotic entertainments like murder as a service. Recycling from the Dumps is a hazardous business.
For people who can't or won't use age, there's barter and many modern transactions in the Sprawl involve both.