Lu covered it fairly well, so I'll just add my
here. Don't get all hung up on the highest power you can find. Remember, the greater the magnification, the harder it will be for you to hold it steady enough to avoid the shakes. Also, with a higher power comes a more narrow field of view, which will make it harder to keep a moving object in sight. If you want to follow a football play, f'instance, a wider field will better allow you not only to follow the play, but to see it develop both across and down field. And if you want to use the glasses in a low-light situation, you'll find that a lesser power and bigger objective lens works best - a 7X50 is ideal for night use, whereas if you were to go to a 10X pair you'd have to get a 10X80 to have a comparable low-light capability - and you ain't gonna find that for no 100 bucks. Finally, make sure you go somewhere you can actually look through the binocs before you purchase, especially to judge the sharpness and contrast of the design. The advantage of sharpness is obvious, and the more contrast will allow you to focus more easily and securely.
I speak from 40 years as an amateur astronomer, and with over 8 years working in a photo shop that sold binoculars, so I know a bit of which I advise - for a change.
