Good morning. Janners is right, Royal Mail 48 (2nd Class) is the cheapest way to post an item if you open a business PPI account anyway. Individual mugs are a pain to post as they fall into the RM "parcel" category so at minimum would be £2.50 for postage and then about 50p for your smash proof box. Coasters, mouse mats and possibly photo frames would come under large letter (if your packaging is not too tall) so could be from 75p onwards to post depending on weight. Note that Royal Mail 48 has a 2Kg weight limit so if you were to post a box of mugs then you need a courier ideally to keep costs down (from say £5). Hope that helps. Olly.