Not only do they pay no income tax, all of their social security tax and Medicare tax get refunded via the "earned income credit"
Also, the EIC is "refundable" meaning that you fan get out more than you pay in.
So, if you had $1000 in federal tax withheld and another $1500 in FICA, you can still get the full EIC back ($5000 average... Google for the various amounts)
So, many get a check from the government of the real tax payers $$$
Cars I've owned '76 Chevelle 350 RIP '82 Monte Carlo 350 RIP '82 Mustang 302 RIP '88 Honda CRX RIP '88 Olds Toronado sold '94 Toyota Tercel sold '99 Acura TL sold 2002 Porsche 911 sold 2003 E46 M3 Blk/gr 2006 MB S430 sold Current: 2008 Infiniti QX56 & 2008 E60 M5