It depends how rune the person is on the other end. If they are being nice, I just say "no thank you" as nicely as possible.
Since I don't make any decisions for the family, but sound a bit like my dad (I think we sound completely different) they call and ask me questions.
If they are going to try and force me to listen to them I have many tactics of lame torture for them. Give them all sorts of excuses, ask them silly questions, or let my little brother tlak to them.

If the same company calls back again, that's when I answer the phone and think up something on the spot to amuse myself with.
*EDIT* The phone wakes you guys up? Man I must be more thankful for being a teenager! I can sleep right through just about anything.