An ASIC (Application Specific Integrated Circuit) is much closer to a CPU than a GPU. To put it simply, it is a purpose built chip meant to perform only one task hence the "application specific" portion of the name.
If you were to buy the chip you see on that website, you would still need to properly attach it to a board. I wouldn't recommend this if you don't have prior experience in soldering and working with computer hardware. Also, Butterfly Labs has gotten a lot of criticism recently. They have thousands of orders to fill and not many have left their production facility yet, so there is no telling when you may actually receive the chips.
If you are looking in to purchasing an ASIC, I'd suggest a business that is using the Avalon chips and making their own units. Avalon has already shipped several hundred ASICs and plans to have their chips out the door within a month or two I believe.
I cannot vouch for their validity, but one company I found that is using Avalon chips to produce mining rigs is Terrhash https://terrahash.com/
If you have any more questions ask away