Check out these guys, psprint.com, specifically their premium
flyers, you can get down to 2" x 2" in dimensions and for 2000 of
them, its just over $100....thats full color both sides...youll have
to punch in your own holes, but for a full custom card with some
pizzaz, you cant beat that with a stick...
Or go simple, use business cards with a completely black back on
them, could serve as double duty....you can get these in smaller
Ive done business with psprint for quite a few years and can vouch
for their turnaround and quality.