General GPS Question in Regards to using ones Phone

While I have a Garmin in transit to me I poked around about GPS use and ones phone. 

Here is what I understand but not sure if I am right. The Phone uses the internet to obtain the map of where you are and where you are going. Once that is obtained then it uses the GPS ability on the phone itself to determine your location. So it's only when it obtains the map(s) for where you are and where you are going that uses data/Internet. 

Now assuming I understand that right, that leads me to other questions:

1. About how much data usage is that? If you don't have unlimited data would that break the bank sort of speak?

2. Can you download maps for your entire state and another and not have to download again unless you want it update?

3. What do you use? Google Maps or whatever?

4. I currently have 2 phones: IPhone 5S (personal) and Samsung Galaxy S5 (work). But I been told Windows Phone is better for this.

Anyone with hands on knowledge or/and a deep understanding for this please assist.

Thanks.

Hmm, I almost feel sorry for you that I'm the only one responding. I won't be able to help with all your points, but I'll do my best since you caught me in the midst of my own GPS quest. So I write out what I know for each one.

1)on Some mapping programs the maps get to be 2.5MB roughly, but I've never seen a mapping app that forces you to use strictly data for the download unless it's an online utility like Google maps is. The Syrgic and Navfree (I have an android phone) both allow downloads via Wireless in which you can get everything at one time and then use the maps offline after that with just GPS. There's a decent GPS app that you get called Easy GPS for iphone. I'm currently looking for an app for android that can do the same thing, which is to locate a specific point on a map with just the GPS coordinates and then find me directions.

2)answered in #1 (yes)

3)I use google maps when my regular GPS has a conflict with things considering there is signal coverage (we travel a bit).(Still looking for a good GPS app)

4)Windows phone is no longer relevant since virtually no major vendor wants to try and support this OS. Just pick your favorite an app will come along to get you what you need. Hope this helps