He's a student though. He might not have a choice - SSDs are coming down in price, but still not that cheap.
Although, thinking about it, it is more likely that he will get an SSD than 16GB of RAM. 16GB of RAM tends to push the price up quite a bit, for some reason.
Both post purchase works out cheaper. Also gives him a large hdd to can use to get some large Unix iso and instructional videos (haha) from other students.