Yeah, that's a USB hub. You can get one if your PC doesn't have enough USB sockets. (But most PCs do, 2 in the front, many more on the back) And I thought you want a controller for the PC? That one seems to be only for PS3. (In case you want to plug it into computer and use Dual Shock 3 drivers on it, they won't work. Only official SONY Dual Shock 3 controllers work with the custom drivers. Even the chinese clones (which look exactly the same) don't work. Anyways, how much you should pay for it completely depends on how much you will be using them. Does your friends meet you at your home a lot? If yes, then it might be worth it. I say get one logitec controller as the main controller you use. They're said to be exceptionally good. (I don't have one) You can also get a wired X360 controller (If you like that layout better) For your friends, you can get cheaper controllers. I have one of these that works great. Or if you won't be playing game that need analog function, cheaper ones exist too. Or you can get something like this, this, or this if you need the analogs.
As I said before, if you already have console controllers, I recommend you to use them as they usually work great, and you won't be paying a lot to get new controllers. Here's a guide for connecting X360 controllers to PC: Wired, and Wireless. Motion Joy has a detailed guide on installing their drivers for Dual Shock 3 on their wiki. And you can use one of these to connect your PS2 controllers to your PC. (I have one, and it works great)
Hope that helps!
EDIT: If you have Wii controllers, they work on PC as well. But your computer has to have bluetooth adapter. If it doesn't you can get a USB to bluetooth adapter) You can also get one of these to connect your Wii Classic Controller directly to PC. (So you won't have to waste battery on Wiimote) (I don't have one)