A new computer. Expect that he will need more than one during his college years.
You know you have to pay an extra "diploma fee", too - right? Yes, if you want him to graduate, there is an extra fee.
We can only guess what books will cost when our kids get to that age. I'm hoping all the text books will be digital by then.
So count the costs that, by then, you'll consider his regular expenses - cellphone, insurance, auto maintenance, etc. You'll be used to paying those things when he is still in high school. In senior year of HS you'll have to pay all his graduation expenses from HS plus all his application fees.Junior year of high school will be his ring and SAT/ACT tests. One of those years you also might want to do some traveling for 'campus visits'.
Do keep in mind that there is tuition and you have to pay for each unit (credits). Many classes are three units and each unit can be a couple of hundred dollars (at least now) so one class is $750. Many students now accelerate their schooling to save on tuition. That means taking more classes / more units per semester. If you have a university in your area (I know you have at least two) run by the campus one day and pick up a student handbook and application. Some universities also have this information on-line. You can check out the current prices.
Like many people said, some schools require freshmen to live on campus - even if their parents live two blocks away. However, you can also consider having him attend a community college for the first two year (make sure he gets his associates degree there) then he can transfer to a 4-yr university for the rest of his education. It is a little more work to do it this way since you have to make sure he covers all his prerequisites, however, it is much cheaper in the long run.
Edited by Cookie2 - 3/20/12 at 5:41pm