I've just noticed that Moo.com are offering free delivery on all orders over £20 from their online store. Free delivery saves £5, so quite handy! Now, if you are trying to use a voucher code, it wipes out the free delivery, so work out which option saves you the most money.
I've ordered the free sample business cards from Moo.com before, and they were really great. What I like about Moo, is that you don't have to order a batch of all the same cards, you can choose different designs in the one batch.
I think I'm going to order a batch of 200 business cards now :)