Thats a good question, about trap vs skeet.
Trap uses one house, that shoots the bird out a headn of the house, at a set range....usually 16 yds, but there are other distances too...
5 shooters at a time, 5 shots, then you rotate to the next station, for a total of 25 shots. Usually only ONE shot although some clubs shoot two birds at a time, so the standard TRAP gun is a tighter choked single shot. In fact many are modified semi autos turned into single shots.
It's a lot more formal, and while the birds can come out at different angles, high and low as well, they are pretty predictable, but are shot at longer ranges so at LEAST a modified choke works best.
Skeet is a whole different animal, the trap houses are on either end of the line, and there are 8 stations. One house is a "high" house, and the other is the "low" house. The first station is right under the High house so when you say pull, the bird comes over your head. You shoot "doubles" at stations 1 and 2, and 6 and 7 right next to the low house where the bird comes out at your feet. Station 8 is right in the middle, andx they more or less come right AT you. You need at LEAST a double barrel for skeet, and it takes some thinking, especially on the doubles, where they both launch at the same time and you have to decide which to shoot first.
Usually about 4-5 shooters shoot a round of skeet at the same time, but they all complete each station before moving on to the next.
Not only is the action much faster, but at much closer range. Choke is open, IC or LESS, I shoot pretty well with my Cyl WInchester 97 Riot gun!
I have never shot sporting clays, but it is supposed to be more like actual hunting....
I shoot both Trap and Skeet, but more for fun than competition, but the competition guys are pretty radical about their stuff and their are some HIGH dollar modified guns out there.
But I have just as much fun with field guns at trap, and while you won't do as well, a field gun on Skeet is fun as well, and REALLY will tell you first how good your gun FITS you and THEN how good a "wing shot" you are...
While the guys are right, the stoegers and the cheaper field guns MAY not work out over the long haul if you are planning to shoot thousands of rounds a month, but for 50 rounds a week or so you will be OK for a while, and if you get into it then you will be looking to upgrade anyway, AND you will have seen and probably have been able to shoot other guys guns so you will figure out what's best for you while learning the sport(s).
When you start out just learn first to be SAFE, and all the range commands and practices, and don't worry about your scores so much.
TRUST me I have seen many a shotgunner with GREAT equipment humbled their first couple of times out, especially at Skeet....and even if you miss them ALL trust me, you won't be the FIRST to go 0-25 there!
But you WILL get a couple even your first time out when you aren't sure WHAT you are doing, unless your eyes are closed!
Bottom line is, the guys who struggle the MOST are the confirmed "rifle" guys with little wing shooting experience, they struggle until they quit AIMING....a shotgun is FEEL and SWING and not AIMING...per se
Just remember....FOLLOW THROUGH....
You WILL figure out what that means eventually, and when you do your scores will suddenly explode....