My DS is going to Uni in the US this year, this is our experience.
He looked at the Unis website to see what the entry requirements, no matter who you are or how many A*s, everyone had to sit the SATs - a bunch of tests sat in 1 day (you're told to never reveal the format or any of the questions or you'll be disqualified from progressing). You can sit the test multiple times, but it costs each time. As DS wasn't remotely interested in an Ivy League school, he just needed to pass and he did pass. I think we paid around £100 for the test. Some American friends pulled a face as he didn't get enough to get into Yale, we asked if their DC did. An embarrassed no was the response.
Next, getting his I20. He has to have this from the Uni to apply for a F1 (student) visa. We had to deposit $4000 into DS financial account at the Uni - $2000 to pay his first semester tuition fees, the rest if we needed incidentals like the $20 cost of FedExing said I20 out to us. We've deposited that $20 because the remaining $2000 will pay the next semester tuition fees. We had to also sign a sponsor form saying we'll be paying the annual costs - tuition fees, accommodation fees etc - which total $12,000. It would be $16,000 if we weren't Latter Day Saints (Mormons). We had to provide wage slips too.
We've applied for a US visa - cost $400 - the forms look daunting, but are pretty standard and we are off to London next week for an interview at the Embassy. So the cost of train tickets, overnight stay (appointment is in the morning) comes to £600.
His course will last 4 years - first year is a foundation year to get everyone up to speed - and the total cost is $24,000 for the tuition fees. His living expenses will be around that too. So we're looking at around $48,000 for a science degree. His medical insurance comes to $3000 for the 4 years.
In comparison, DD2 is at Uni here. It's £4500 a year for her accommodation, £9000 for her course fees and another £4500 living expenses. £18,000 a year. Her course is only 3 years £54,000 in total.
I'm sure cost wise to us would be the same if we weren't LDS regarding our sons degree, but it's no where near the $70,000 a YEAR we were told by well meaning friends.