You will find many Asp.net Shopping Cart Tutorials all over the internet, but is it really worth it to build your own from scratch?   If you are doing it for fun, or have a small budget or no budget and don't like the Free shopping carts out there, than why not!  

But the big question to ask yourself is... why are you cutting a huge corner on the most important aspect of your online business?  But more importantly... do you really want to take chances on building this yourself.  What if you misunderstood something or completely overlooked something?

There are many things to consider when building a cart using a tutorial.  First, the most important thing to consider is that the tutorials usually cover some very important topics briefly.  For security reasons alone, why try to build one yourself?  This is just one example, but is a huge issue for many is overlooking things like SQL injection or Cross-Site scripting vulnerabilities.  

The point is, there are dozens of things you need to do that are more than likely not really discussed in the tutorials.  Why not invest a little in your online business and do it right the first time?