I just used Uber to travel from Art of Animation to Universal and back this past Thursday. It was $21.59 to go to Universal at about 8:30 AM with surge pricing, and only $13.56 on the return trip with no surge pricing. This was to take 4 people each way, so if you split the fare, it's pretty cheap. For us it was even cheaper than that; I referred my dad to Uber, which gave each of us 1 free ride worth up to $15. So we paid just over 6 bucks to go there, and nothing to come back. Really can't beat that.
All you do is download the app, setup a username and password, link a credit card, and then tell it where you want to be picked up. Once you do that, there are a couple options. One is "fare estimate", which will give you an estimate for your trip. If you go back, there is another button saying "request uberX"; you press that button, and it'll tell you how long it'll take the driver to arrive (almost always less than 10 minutes on Disney or Universal property). In the meantime, you tell the app where you want to be dropped off. After this, it'll tell you the driver's name and give you a description of their vehicle so you can keep an eye out for it. As it approaches, just wave them down and tell them who you are (they'll tell you who they are as well) and hop in. After the trip is finished, your credit card is automatically charged for the fare of the trip. Be warned that if you wish to tip the driver, you have to give them cash; there is no way to tip through the app.
I hope this helps.