I would say you are poor if you make less than $35,000 per year.
That's like $17 per hour, and you aren't going to be paying any taxes if you have even one child. Doesn't seem that poor to me.
If you have one child at that pay, you are going to really struggle to find a place you can afford to live without having to share a room with that child.
It is pretty easy to find a two bdr apartment or even 2 bdr house to rent for $500 or less.
Licknecky is right. Once you get down to a full time job at like 18k a year that is real poverty. Full time at minimum wage is just over 15k per year. When I think of working poor I think of Mom working 30-40 hrs/ wk at close to minimum wage and Dad working 60+ slightly above min wage. It's worse when Mom is 60+ at near min.
When I think poor, I think of anything less than middle class. Somebody making $35,000 per year would have a monthly paycheck of just over $2000 after taxes. If they rent a $500 apartment, pay $500 per month for daycare, $100 per month for electric, $70 per month for gas, $200 per month on food, $100 per month on gasoline, and have a $200 car payment, that only leaves about $300 per month. That is living with no cell phone, cable, or internet.