Just as it claims to be. Well done.
Well written and the code is clean and at least a good foundation for a functioning shopping cart. I appreciate mostly how each chunk of code is explained and examples are given.
If you use the scripts Bintu gives, you'll be up and functioning in a weekend, as claimed. However, if you are seeking to understand the code you are implementing and wanting to type it in as you read, it will take longer, but such is the price of understanding.
The cart features are visually very basic, and this is great. The user can implement their own styling to this.
There's not a lot of discussion about security and the cart is simple enough that generally good PHP / MYSQL security practices will cover it. One think perhaps left out of the discussion is PCI compliance vis a vis credit card numbers, which the user will have to research. Lastly, there is not discussion about automatic shipping cost calculations, however, the foundation laid in working with PHP may make it easy enough to integrate UPS / FedEx, etc. API's into this cart system.