AttackOfTheMoons

It cancer. It will have 1000ms+ ping. Mobile on the other had will have better ping. Just did a test on my phone. Tmobile offered me about 27ms of Ping, 60 Mbps down and about 2 Up. Which isnt too bad if you ask me. Comcast on the other had offered about 10 ms, which is farily good for cable internet. Fiber internet has much lower pings generally speaking. 
 
The issues with Mobile internet is speeds will vary, and depending on your provider there might be restrictions. Hotspot and Teathering data at least in the US is treated much diffrently than using data on your phone. For example T Mobile only offers a max of like 20 Gigs of Hotspot data before you kicked to 3G speeds. Most providers have simular practices. Satelite internet on the other hand can have daily and monthly usage caps. I mean fuck, Hughs net sent us some marketing material and they said once you cross the threshold you get like 1 to 3 Mbps. Fuck that. 

I think the first link you did was more of an Access point than a site to site wireless link. The TP Link device is acutally the type of devcie you are looking for. It specifically states its for WISP's (Wireless Internet Service Providers), which means it would work for your purpose. But like others have said, it uses an older wireless standard meaning speeds might not be great. 
 
The first link @kirashi provided seems like some kinda of over kill solution. However the second link seems to be more on the AirFiber products and from what I have watched on Youtube and read, these works fairly well. And some of them utiltize 5Ghz rather than 2.4 Ghz. The higher bands provide better speeds. While 5Ghz does have less range and less penitration power  it also have less shit that will interfere with it. Bluetooth, Microwaves, cordless phones and many other wirless devices use 2.4 Ghz because it doesnt require any special licsense to use. While 5Ghz tends to have less devices utilizing it. Also range shouldnt be an issue seeing how many of these Air Fiber products are rated for several KM. 
 
All that being said it comes down to a few factors. 1) How fast is the internet connection your trying to share? 2) What are you realistically looking to achive here in terms of performance?  

One thing you should consider is the speed you expect. The 300Mbps APs use an older wireless standard and slower speeds (around 60Mbps in reality). The 5Ghz ubiquiti one can give some good results for you but having some obstacles in the way is worrying.

even the DIY route seems very unlikely to stay within the budget, if not going for refurb/second hand devices.

what he linked is a (more or less) connect and go solution for connecting two buildings with "more or less line of sight" together.
 
also, you'll most likely be beyond the 200USD point quicker than you'll imagine. a decent wireless access point is already very close to that.

I don't really see how you're going to achieve that with just $200, unless you go the DIY-route, which is gonna be a lot more work: you'd need to find two used routers that support OpenWRT and which have removable antennas, then find two highly directional WiFi-antennas, a laser-pointer or similar for aligning the antennas towards one-another and then configure a wireless bridge on both routers within OpenWRT -- it's certainly doable and produces good results, but premade solutions definitely are the easier choice.

No idea, I don't currently work with UBNT products beyond drooling over their Edge Router, UniFi AP's, and CloudKey's at the moment, as I don't have the surplus monies to replace my current networking gear. You may want to contact a distributor in your region, or start performing research / wait for someone more knowledgeable to come along and help answer that for you.