They're very cheap now. What you want to look out for is your burner type. When I first bought DVD Rs I didn't realize there's DVD+R and DVD-R, I thought they were the same thing since there's only CD-R and no such thing as CD+R. But some DVD burners will only burn one or the other and some DVD players will only play one or the other.
Needless to say, I was frustrated when I found out I had just bought $30 of 50 blank, completely useless discs. (The price has come down since then I think).