That's 6 to ten years depending how far they took it.
2 semesters a year, 6 years, 18 grand a semester... $216,000.
Well that's an imaginary number that doesn't include drawing a living allowance from their loan or interest.
Raj would have just paid his automatically and as a foreigner, his course wouldn't be subsidized by the government, so his fees would actually be 5 to 10 times greater than a US citizens.
Meanwhile there is no way that Sheldon didn't have a thousand and one scholarships.