Cheap upgrade 3rd monitor

Hey guys, I have been needing an entire system upgrade, but that is funded by my parents who think I don't need to right now. So I have had this 3rd monitor sitting around since my system only has 1 PCI x16 slot. I have 2 PCI x1 Slots and I was thinking, should I get a x1 video card to run the 3rd screen only? Obviously not for gaming, but would it be enough for youtube and etc? I was thinking of this one,

 http://www.amazon.com/Zotac-64-Bit-Video-Graphics-ZT-60607-10L/dp/B00CIDFP70/ref=sr_1_1?ie=UTF8&qid=1405052318&sr=8-1&keywords=pci+1x+video+card 

I currently have a GeForce 8400 GS, (old I know) and its good enough to multitask on 2 screens. It disabled my internal video card too , so I can't use that. would getting a second graphics card even work?

Thanks in advance