Cracked iPhone screen? What to do? - 2

So I dropped my phone & the front screen broke. I'm with Verizon so we went to a Verizon store to try to just use an upgrade and get a new phone but it was really complicated and wanted to change our plan all around and I don't want that because we have about 5 phones on the plan. And 2 phones have unlimited data but if I use an upgrade, they'll cut off the unlimited Internet on those phones and I don't want that. I called apple and they said it'll be 149 to replace the screen. The guy I talked to also said if I went anywhere else to replace the screen, if for some reason I had an issue where I had to go back to apple for my phone, they can tell if it's a different glass and that'll void the warranty. But i don't know what that warranty is? I don't even think I have a warranty. I bought the phone from a Verizon store. So what can I do? And the guy said something about apple care? I don't know what that is?

Basically the warranty covers anything but broken glass pretty much. But I've broken many iPhones and get them replaced with non apple parts from repair places and not once when I went into the Verizon store for a different problem have they said anything about me using different glass, and if they do you could take it to the apple store because they have never said anything to me about it either