You are right Karl but the shopping cart which you'll end up creating will be something which just serves the bare bone needs. Some of the other features of a

You are right Karl but the shopping cart which you'll end up creating will be something which just serves the bare bone needs. Some of the other features of a shopping cart 1. Integration with a checkout system (Single page Vs Multi Page) - this is itself a demon in itself. 2. Bells and Whistles on the cart itself like tax & shipping cost estimator I guess when you say you can create a shopping cart in 15 mins you are not keeping in mind any checkout flow integration or estimators or much control with items in the cart e.g. changing sku options like color etc. There are some open source systems like Magento which can be looked at too.