Profit-sharing citizenship the Reavers dangle in exchange for surrendering your body and cycles of unpaid soldiering.
Explaining Gunnery Sergeant X2, The AI lays out how Reaver citizenship works. Unless you are a vat-born progeny of The Initial, gaining citizenship — with its profit-sharing and financial benefits — is an epic pain in the ass. First you must lose your biological form; that initial "upgrade" is free. After that there are only two paths.
One is paying for the upgrades yourself, usually a non-starter, since the only employers who will hire someone who let the Reavers swap a good hand for an expensive grasping claw are the galactic equivalent of a Wendy's or an interstellar carwash. The other is working for the Reavers for free: food, housing and unlimited health care, plus exactly one more upgrade per three-cycle deployment — more if something gets shot off. That work means being dropped feet-first onto land leases to evict settlers so the Reavers can expand their factories. X2's own path was a 400-cycle journey, ended by Tina's jaws.
The economic trap that manufactures Reaver cyborg soldiers out of desperate recruits.