Go to their ‘Buy Online’ section and order your books of stamps here (or your Special Editions, ready stamped envelopes or personalized stamps). You do have to order quite a lot of stamps but it’s the easiest way if you’re going to be posting lots of mail in the near future. Alternatively download ‘SmartStamp’, which allows you to print your postage directly onto your envelopes from your own printer. You can also find the package and letter weights and costs table here for the UK and overseas and look up addresses and postcodes.