I absolutely agree with what everyone's saying in this thread. cheap walmart racquets plus a couple cans of balls would be more than enough. As for the vibration dampening, the soreness is more from mishits (hits that land outside the sweet spot in the middle of the string bed). When you hit a ball, the racquet will flex a little. With the cheaper racquets, the racquets tend to flex more and twist out of your hands on a mishit, thus contributing to the "more soreness idea". However, once you get the hang of hitting the ball square on the strings, there shouldn't be any soreness. If you're worried about vibration though, just pick up a vibration dampener for a couple bucks, and it'll work wonders on any racquet you buy.
SunnyD is right in saying that the first thing you should do is to keep your eyes on the ball. However, what's the point in keeping your eye on the ball if you can't hit it correctly? The ideal grip for a forehand is what is called an Eastern grip. The analogy we like to use is the hold the racquet like a hammer, and you're using the edge of the racquet to hammer in nails. This keeps the face of the racquet perpendicular to the ground. You want to make contact with the ball when it's slightly in front of you. If you're right handed, take a step with your left foot before you hit the ball. this turns your body slightly sideways and allows for hip rotation, which is key in hitting a good shot. Many people think hitting a ball is all in the arms and wrists, when actually it's in the hips. Sorry, it's hard to explain in words, try and find someone who plays to show you the ropes. The best way to learn correct form is to emulate someone else.
Another tip - don't try and learn from the pros you see on tv like in the French Open. Tennis can be a complicated sport. We get a lot of kids who, after watching an Open on tv, come to their lessons trying to hit 150 mph serves like roddick or attempting to use extreme western forehands, which is what 98% of the pros use, and that doesn't help them any. Learn the basics first and learn them well, and then you can build your game. Tennis is a game you can play for life, so I hope you stay interested in it!