You can ask them. I can't say if they will or not. I had card boxes and pencils that I had gotten at various times.
I will say that I went through a lot of stuff on the givaways!
On the other hand, if you have a lot of common and/or uncommon cards, giving one out to each kid would probably work just as well.
One of my League Profs put down some extra cards for the kids after I ran out of goodies and they generated more excitement than anything else!
Another idea that I have, and just haven't implemented yet, is to use Badge-a-minit to make badges for the kids using empty packs that I've been saving.