Ian, I've used "special offers" on cheaper leaflets before but they don't seem to work for me, so I've moved over to cards and no offers with a better response.
The post card seems better from many points:
1. Easy to carry and post, pushes past the flaps & brushes whithout ending up in a
crumpled mess on the other side of the door.
2. Easy to store for customer, notice board, handbag.
3. Because of its size can also double up as business card but is more visable.
Only had them yest. as prev. stated and have already been very lucky for me, as I attended a business seminar yest run by local radio station and on registration a business card/ postcard was put into a prize draw and I won a digital radio!
regards rob