I chose the cards for my oldest. He is 12, autistic, and adhd. I have purchased cards by School Zone before (the people, who created the cards) from a few different stores. The price on Educational Toys Planet is comparable to other places.
Each card is represented by a picture and a letter. My technique for teaching my son came from his speech therapy teachers. Show him a card, say the letter, then say the word. See if he will imitate the letter, the word, or sounds similar to the letter or the word.
The deck also has extras. For example, there is a card included from the Golden Scholar Club, where you can redeem it online for a free book. Another card has ideas for games, you can play with the cards. For example, the alphabetical order game, where your child tries to place a set of A to Z in Alphabetical order. Finally, there are three cards, with mini pictures of all the letters with matching pictures.
I received one or more of the products mentioned above for free using Tomoson.com. Regardless, I only recommend products or services I use personally and believe will be good for my readers.