The data that we have is a combination of sources, the most important of which is a database of many of the known components in the world, past and present. This is important because you might want to know about a part that is on your board (especially the parameters of that part) even if you can't buy it today. This could help you find a replacement for it. The pricing data that we have comes from our sister site, FindChips.com. This data shows all of the available stock at distributors around the world.
It is entirely possible while searching for a part that you will find something that does not have a price, stock or either. This is due to how we update our data in order to make your searches as fast as possible. If you're looking for a component you can buy today, we suggest that you click the "true" button on the "Has Stock" parameter in the filters at the top of the page. If you want to wipe this out later and see all of the available parts, even if they're not in stock, you can wipe out that filter:
Once you click on the price, you can view where it has stock.