Rory make some good points. alot of answers to your questions are already floating around in other threads on the board.
however, since i always hated getting that response from people when i was new to a board i'll give you an idea of some dekes to look at. you'll have to decide what you want.
not sure what you are planning to hunt. i assume mallards are prominant down there as they are just about everywhere.
here is what i would recommend as a "starter kit" for a new duck hunter. obviously, every has their own different ideas, and this stuff may or may not work for you, but it should help a bit.
one dozen Green Head Gear HotBuy mallard dekes from Avery. you will need string and weights for them also.
total cost - about 30 dollars
decoy bag - if you are going to be using a cart or boat to carry stuff in. get the cheapest sack you can find to put them in. if you are going to carry them on your back, spend the money and get a good "backpack" style bag.
cost -15-30 dollars
Call - not really needed, but i would look at a Haydel "Red Leg" or the DR-85. also, Primos makes some good ones to egt started with. you will, undoubtably, being giving this call to some kid down the street within a year, so don't spend a lot of money on it.
cost - around 20 dollars.
there, that would be a good hunting set up for just about anyone. most importantly though is to take a look around and find stuff you like. see what other people in your area are using.
Friends Don't Let Friends Shoot Mossbergs.