OMG I just got a betta fish & I don't know how to take care of it... Which tank should I get? PLEASE HELP!?

I didn't look at your links, but betta fish don't need a very big tank to servive. I would get a small 5 gallon tank, and remeber you can't put more the one in the same tank. Also when putting a new fish into a new tank you should fill the tank up with water and let it sit over night before putting the fish in. This allows the water in the tank to settle.Plus if you take the fish from one tank and put it in another the water temp may not be the same, and it can shock the fish.