> say "No, I want to talk to my lawyer, I don't want to talk to you,"

And if I can't afford it, I'm going to get the money for a lawyer ... where?

If I don't have a lawyer, will I just sit in jail until I talk or get a lawyer?

What's the real, practical advise for someone down at the margins?

You don't ever have to talk at all, lawyer or not.

If they want to play hardball, they can detain/arrest you, but there's a limit on how long they can do that before they have to formally charge you. If they need you to talk to them before they'll feel like they have enough to charge you, then they probably won't charge you if you keep your mouth shut. Yes, the experience will likely be incredibly awful overall, but it'll probably be better than what will happen if you -- even accidentally -- lie to the FBI.

And if they do decide to charge you, despite your silence, then they'll still have less to go on than if you talked (and likely accidentally lied to them). At that point, if you truly don't have the means to hire a lawyer, you'll at least get a public defender. Yes, they're almost universally overworked and don't have the time to give your case the attention it needs, but it's still better than accidentally lying to the FBI and giving them an obvious crime that they don't need to do any more work to prove.

There is really just no upside to talking to the FBI (or any law enforcement officer, for that matter), and plenty of potential, likely downside. It's a huge shame, because I wish we lived in a world where law enforcement's primary purpose is to help and protect people, and not to help DAs and prosecutors find reasons to jail people, but... well, that's the world we live in.

Yep to all that.

But. Meanwhile, you've probably lost your job, either for not showing up or for being arrested. At least then you can argue that you're indigent and need a public defender.

INAL, but they can't hold you indefinitely without charging you, and once you're charged you can be assigned a public defender if you can't afford to hire an attorney.

Note that you have to actually prove that you are indigent and can't afford to hire an attorney yourself.