The tennis racquet may be the most important aspect of tennis. To have a good game you need to pick the best racket. Keep in mind the grip size and the head size. Also keep in mind your budget. There are expensive models like the pros use and more affordable rackets that are still great.
Pick a racket with the grip size that you need. If you are a junior player stay in the 3 and 4 range. Four and up are for adults. 4 1/4 is a perfect size for most girls. While 4 3/5 are best for most males.
The head of the racket is the place where the strings are and also where you will aim to hit the ball. Head sizes vary between 85-105 square inches. The bigger the head size the more power your game will have but you will have less control.
You can find an array of great tennis rackets on EBay. The top brands are available there. Just look for grip size, head size and the overall wear and tear if you buy a used one.