Hey Ivan, the product you posted is a wifi hotspot, not a phone. All that device does is it acts like a router (it's not a router, no dhcp and such, but that is another topic). All it does is provide internet access. What you need is a phone. I know you are not wanting to spend a lot of money and this may not be a long term thing, so I think China is your best bet. below is a link to a phone with a 4.5" screen (not the largest out there, but bigger than something like the iphone 4) and it runs on the Android 5.1 OS. It also has 1GB of RAM so it should be able to handle the video coming in pretty easily.
It has WiFi so you will be able to get the signal from your quad. It also has bluetooth so if you have an Ikon or when you upgrade to a Naze32 or CC3D quad (you will, trust me!!!), you cna use the bluetooth module on any of them and use this phone to program them without a computer. It's freakin' awesome lol.
For the price (less than your hotspot), I may get one myself just to test it out. I can't say anything on quality and we all know china pads their reviews themselves. so take the reviews with a grain of salt. I'm just trying to get you into this as cheap as possible and still give you something that you guys can actually see. Hope this helps.
VKworld F1 4.5 Inch 1GB RAM 8GB ROM MT6580 1.3GHz Quad-core Smartphone Sale - Banggood.com