Welcome to Android Central! I assume that you mean you get 1200 of each of those items
per month, correct?
Mobile phone minutes refer only to calls you make. The 1200 mb of data is when you're connected to 3G or 4G and sending or receiving data. Remember that you don't have to be actively doing anything to have your phone use data, since it is often doing some background syncing and updating. If you use wifi to connect to the web, then your mobile data connection
should turn off temporarily, thus preventing you from using up more of your data allotment, but this doesn't always happen depending on the phone. In this situation, it is often a good idea to turn off your 3G/4G connection while on wifi to ensure that you're not using up your mobile data.
1.2 GB of data per month is fairly average for the moderate user. If you plan on streaming a lot of music or videos while not on a wifi connection, then you might need more.
GPS itself does not use mobile data, but apps that use the GPS can use mobile data (like, for example, Google Maps). GPS isn't entirely necessary unless you need a precise location--without GPS, the phone can triangulate your position within reasonable accuracy (say, around 1000 feet) using the cell towers or the wifi address.
Please be aware that the ZTE Valet is very much an entry-level phone. Its specs (
ZTE Valet Specs, Features (Phone Scoop)) say that it has 512 MB of system RAM, which is pretty low these days (most phones have at least 1 GB, and high end phones have 2 GB). Low RAM means fewer apps can stay in memory, which means more sluggish performance and app switching. It also only has 4 GB of onboard storage ROM, of which only 2.3 GB is available to you. This storage ROM is the only area where you can install apps, so it will limit how many apps you can install, and how big they are. Inserting an external microSD card will not allow you to install more apps--it's mainly good for storing media files, like music, photos, videos, etc. If you can afford it, and if these things are important to you, I would suggest finding a phone with at least 1 GB of RAM and 8 GB of storage ROM.
Good luck!