Tarot bags are a very popular way of safely storing and protecting tarot cards. My favourite bags are Sulis's handmade tarot bags. She makes gorgeous velvet and silk lined bags in a number of colours, styles and patterns, and reading cloths as well.
Other quality tarot bag retailers include Wyldechilde Creations and Tarot Totes.
Lo Scarabeo also sells tarot bags that match their tarot decks on Amazon.com. These are some examples of their bags...
There is also a wide range of tarot bags and pouches on eBay - patterned, decorated, embroidered, velvet and more.
For something sturdier to keep those special tarot decks, there are always tarot boxes.