For people who are living in poverty, many will jump to the opportunity of gaining fortune that is found in the US. Immigrants who come over to the US are often in debt or too poor to support their family. Since the US is said to be the mountain of gold and riches in some cultures, people of all classes want to come here and seek their fortune.
Furthermore, many immigrants who come here have great gratitude in the rare opportunities the US provides. One, there is more access to modern techonology. In some third world countries, many people don't even have access to a computer or to a library. Here in the US, most of these services are free and the opportunity to use these services are unlimited. In addition to access of techonology, there is also financial support from the government.
For immigrants who can't support themselves, they can get money from the government in forms of SSI, welfare, or food stamps. The US has the ability to help out poor people whereas in some countries, one has to work for survival or die by starvation.
The drive to have a better life and make more money have once been the leading factors in drawing immigrants here. Whether the immigrants are legal or illegal, the promise of a comfortable life is too much to pass up.
Flanakin, Duggan. "Addressing the root causes of illegal immigration." CFACT. 24 Jul 2006
“This month in immigration history.” US Citizenship and Immigration Services. 21 Jan 2006 US Department of Homeland Security. 11 Jul 2006 <http://usics.gov/graphics/index.htm>.