Robert Rector and Christine Kim of the Heritage Foundation calculated that an average low-skilled immigrant household costs federal, local, and state governments $19,588 per year more than it pays in all taxes.
Rector and Kim concluded that low-skilled immigrant households pay $10,573 in taxes per year. As the following chart shows, Rector and Kim took every possible tax collection method into account, including sales tax, the purchase of lottery tickets, and user fees:
The study also shows that low-skilled immigrant families receive, on average, $30,160 in government benefits each year:
The study by Robert Rector and Christine Kim concludes that American taxpayers spend a total of $89.1 billion on some 4.5 million low-skilled immigrant households (comprising some 15.9 million individuals, or roughly 5% of the population of the United States), costing each non-immigrant American $330 per year. The study also notes that about 60% of these households were headed by legal immigrants and about 40% headed by illegal aliens.
You can read the full version of The Fiscal Cost of Low-Skill Immigrants to the U.S. Taxpayer at the Heritage Foundation's website.