1. www.favoritepostcard.com – best postcards and stationery shop for postcrossing! Shipping worldwide! Postcards, washi tapes, envelopes, stickers and more! Postcards from 0,29 EUR.
  2. www.redbubble.com – space to share and buy art.
  3. www.postallove.com – postcards from Poland.
  4. www.bookdepository.com – lot of postcard books and sets.