Get a quality mask first.
For the gun...magfed is great for me and I love playing it but i would check with your friends first. If they all shoot electros and all the fields they play at draws the same just know that a magfed will put you in a disadvantage in terms of rate of fire, etc. Maybe see if they play pump games in your area? A empire traccer is cheap and has a milsimish look to it.