This goes out to anyone who has enrolled before: What do I get for my $600 deposit? A sweater, t-shirt, hat? I'm just curious because I like free stuff (if you ignore the $600...).
Not really sure if you're joking, but if you're not, the deposit ensures that you have a spot waiting for you at the beginning of the year. If you don't pay the deposit by the deadline, your spot is relinquished. Some schools are nice and will remove the deposit from your first tuition bill so you don't have to pay extra, but I don't know if Hopkins does that.