Depends on if they opt to take it. IIRC, released wrestlers can choose whether or not to accept the 90-day deal. If they accept, they'll get paid for the 90 days, but can't wrestle anywhere else. If they decline, they don't get paid by the WWE, but can pick up bookings right away (which is what Raven did when he was released).
If I'm wrong, feel free to correct me.