This is the EIA website and it shows where our oil comes from.
http://www.eia.doe.gov/pub/oil_gas/p...nt/import.html
Oil in Mexico is much cheaper because it is still a developing country. They dont have the income for everyone to own cars, like the US does. Therefore the people rely on public transport, and the demand for oil in the country is much lower. Since the oil comming out of the ground is not costing $130 a barell, it is just a fututes marker, the oil companies have the ability to sell at prices that fit demand in that nation. Also they have tons of oil to sell that they do not need, so the profits then benefit the country the oil comes from.
Hope that answers your question, and hope everyone soon realizes that its not just the saudi's that are raking in money from us.