The first step in choosing the right Tarot card deck is finding one you feel connected to. Many people make three mistakes in buying a Tarot deck. First, they buy one that a reader they went to uses. Secondly, they buy one that they feel they "should" read, for example a pagan feeling they must get a pagan themed deck. Lastly and most importantly, listening to myths such as you can't buy your own Tarot deck. Once these mistakes are eliminated your next step is finding the perfect deck. Although not at all necessary, I like to make this a Sacred event. Whether I choose a day to stroll looking for one, or I choose to search eBay or such online sources. Don't be rushed, be calm & search through many decks first. Try to find a site such as aeclectic.net that gives pictures of most decks or type the name of the deck online and click on images. This will show you images of the deck. If you are unsure, wait. It is best to wait. There were many times I was unsure, but grabbed a deck and later ended up selling it. You can buy a used deck, however you should cleanse it with sage, salt or Moonlight. Remember a deck should feel comfortable to you. The images should speak to you. You should connect to them. I purchased a stunning deck years ago a computer generated deck that was a masterpiece. Yet, when I tried to read with it, I couldn't connect. Just because a deck looks beautiful, doesn't always mean you will be able to read with it. Then, I went through a stage where I believed I had to have a Marseilles Tarot, as that is a classic deck. Yet again, I didn't connect. Connecting to a deck being able to read with it, liking the pictures are very important. Your Tarot cards should be like an old friend, they should make you feel comfortable and at ease. This way you will want to read with them and can enjoy them. Another thing that is helpful is to know what you like & dislike. I for instance know that although I adore computer generated graphic decks, I don't read well with them. And although I respect the classic decks such as the Marseilles or Visconti, I prefer decks with illustrated pips. So, these are all things to consider.
My first deck was given to me when I was young it was a Rider Waite deck. After reading reviews how it is masculine or wasn't nice, I purchased several decks and read with them. I of course always reverted back to the Rider Waite deck. And now only use that and a French Lenormand deck for readings. So, go with your gut. If you are looking at a deck and unsure or uneasy, set it down and wait for another day.
There are many sites such as eBay, amazon and half.com which is an eBay site, where you can buy decks inexpensively. Go with your gut. Try to see a few images of the deck , not just the ones on the box. Some decks don't have pictures on their pips or Minor cards, and if you want pictures on the cards, make sure the deck does. Get a good Tarot book, but most of all go by your gut. These are your cards.
Some of my favorite decks, The Rider Waite Smith, Enchanted Tarot by Amy Zerner & Monte Farber, Osho Zen.