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A decent pair of binoculars costs less than a decent telescope. Most are lightweight and easy to use as they provide a wide field of view that makes it easy to find your target. It also helps that the images are right side up, unlike upside-down or flipped images in many scopes. Best yet, you might already have a pair at home or can borrow one easily.
The exit pupil of a pair of binoculars is the diameter of the beam of light leaving the eyepiece and entering the eye. It is calculated by dividing aperture by power.
For eg. 7x50 gives a 7mm exit pupil and 10x50 gives 5mm.
The ideal human eye opens to 7mm in the dark but most eyes can't reach the full 7mm and the excess is thus wasted. As we grow older, our pupils will open less so an exit pupil of 5mm or more is good.
An important factor is the weight if you intend to hand-hold them. Most people should be fine with 8x40/7x50/10x50. It is best to try out the binoculars yourself, compare them with other models and decide what YOU can hold steadily for long periods (bearing in mind you'll often be tilting your neck back).
Eye relief is the distance your eyes must be from the binocular eyepieces to see the whole field. If you need to wear your eyeglasses (especially the ones that correct astigmatism) while viewing, you need longer eye relief. Again, make sure you try the binoculars before you buy.
Cheaper models are made with BAK7 type glass. BAK4 type glass is gives brighter images but costs more. You can check by holding the binoculars pointed at a light with your arms extended. Look into the eyepieces, squared-off edges are a sign of lower quality BAK7 prisms. If you can only afford a cheap pair, they can still give you decent images, just test them first.
Avoid ruby coated binocs where possible as they are known to give greenish-tinged images by reflecting too much red light. Some people however don't see any difference.
You'll find that the longer and more often you study the same object, the more you will see.
Binoculars
Binoculars make good astronomical tools. They won't show details on planets but some stellar objects are BEST viewed with binoculars, like m31, m33, m42 etc.
Choosing Binoculars
The most common binoculars for astronomy are 7x50 models. 7 is the magnification (objects appear 7 times bigger) and 50 denotes the aperture (diameter of each front lens) in millimeters. The larger the aperture, the brighter the images appear. On the other hand, higher powers cannot be hand-held.
The Pleiades. 7x50s (left) show a wider field than 10x50s.
BAK4 prisms do not have squared-off edges.
Coatings
Optical coatings improve image brightness and contrast by reducing reflections. Check the lenses by looking for a coloured reflection (like blue, green, purple). Multi-coloured coatings cost more.
Things to Note
Avoid fixed focus binoculars. Some binocs are rubber armoured and this makes holding more comfortable. Most binocs have rubber eyecups which help keep out stray lights.
Tips When Viewing
Give your eyes time to adjust to the dark before viewing. Use a chair with a reclining back and support your elbows on the arm rests to reduce dancing views. An alternative is to lie on a mat or use a rubber dinghy. Larger binocs (11-20x) should be mounted on a tripod.
What Can I See?
Besides a whole lot more stars, you can also see 3 or 4 of Jupiter's moons, Saturn elongated (due to the rings). A higher power binocs will show the rings distinctly. Bright comets, asteroids and a dazzling view of the Pleiades are within reach. In short, many objects visible through a small telescope will be available to you.