There are three "versions" of the regular Tag reader:
1. Comes with the "Ozzie & Mack" book. It has 16 MB of memory and holds about 5 books. This was the first released. It is available in pink and green. This version will also read Tag Jr. books.
2. Comes with "The Cat in the Hat" book. It has 32 MB of memory and holds about 10 books. It is a more recent release. It comes in pink or green. This version will also read Tag Jr. books.
3. School Tag reader. Only available online from leapfrogschoolhouse.com. Has about 80 MB of memory and can hold about 25 books. This one requires different software to use and will NOT read Tag Jr. books. It is also considerably more expensive and there is a lag time between when books are released and when they can be put onto the School Tag.
I have all three versions. I would recommend choice number 2 (it is a good mix of holding quite a few books and lower price. If you want to hold more books at a time than 10, it is cheaper to use the coupons and buy two readers than to get the orange one. I bought my School Tag before the 32 MB one was available or I probably wouldn't have gotten it. As a previous poster mentioned, there is a Target coupon for the Tag reader and there is also a $10 off coupon for it floating around (do a search on the board and you should be able to find it).
There is also a Tag Jr. reader. It will only read the Tag Jr. books and will not read regular books. It looks like a two snowball snowman. This is NOT the one you want.