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If you don't have a set of binoculars, they are a common enough item at flea markets and yard sales. A word of warning here, a large percentage of binoculars you find this way have problems.
Before you buy a used set check them out. Do the images merge like they should or do you see double? Reject any that show a double image. Normally you will be looking at them durring the day, so look at the furthest thing you can see with them and check the focus. You should be able to get a sharp focus in both sides. When you think you have them focused, close one eye, is that side focused perfectly? Repeat for the other side. Reject any that do not focus properly. Check them out for mechanical defects. Can you wobble either of the eye pieces? Is the hinge loose and sloppy? Are the objectives (large lenses) tight? Again, reject any that have problems. Avoid really light weight binoculars.
What type of binoculars should you look for? First and foremost don't buy a set so large that you can't hold them steady. Really large binoculars need a tripod and mount to give good views. Binoculars are normally marked with 2 numbers as such: 7X35 or 10X50 or 8X42. The first number is the magnification, the second number is the size of the objectives in millimeters. The larger the objectives the more light they will gather. Binoculars larger than 50mm are normally too large and heavy to hand hold steady enough for good views, and some people may find even 50mm binos to large. The most popular and common ones for astronomy use are either 7X50 or 10X50. Avoid anything with more magnifaction the 10X, again they would normally require a tripod and mount to keep the view from jiggling around.
Without a great amount of searching you can probably find a suitable pair of decent quality binoculars in the $10 - $30 range.
First rule of using Binoculars is DON'T DO THIS:
Here are two pairs of binoculars I was able to buy dirt cheap:
This pair of Pentax 7X50's where purchased for a whopping $6.00 at a yard sale. Deals this good are rare, I would say that even at $20 a pair like this are well worth buying if they don't have problems.
These Sears 7X50 wide angle binos cost me $10 at a yard sale. They have as good or better (I think maybe a smidgen better) views as the Pentax set, and a wider view. Since I bought them I tend to use them more than the Pentax.
I picked up this set of 16X50 Binos at the Fleamarket for $10. These also passed my madatory inspection for used Binos.
16X magnification is so much in a binocular that you can not hand hold them and not get jittery views. After a little experimentation,
I came up with a way to mount them on an extra EQ1 mount:
With them mounted so they are steady, I have no problem easily seeing all 4 moons of jupiter, which is quite a sight in binoculars. The do have a glare issue when looking at Jupiter it's self, but 16 power isn't going to bring out any detail on a planet. With a 3.5 degree Field of View they frame up something like M-44 (the Bee Hive Star Cluster) rather nicely, in a 7X50 bino the cluster looks very small, and in most telescopes the whole cluster doesn't fit the FOV.
For day time use I can read a licence plate from about a 1/4 mile. ;)
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