When choosing a kids microscope, you should decide for what purpose it will be used. If you are going to examine slices under a beam of penetrative light - you'd better take a classic monocular microscope. From the title it's quite evident it has an ocular, therefore a kid would use only one eye. It is not very convenient, particularly for children - their eyes grow tired quickly, and it is difficult to get accustomed to looking with one eye through a microscope keeping the other eye open at the same time. However, skilled biologists constantly working with the microscope are able to do it - they just relax and open both eyes and then focus on the image in microscope. This technique can significantly reduce fatigue, but children won't master it simply, because they often struggle to screw up the eye tight, and grow tired very quickly. Such microscopes also have an advantage - strong magnification.
8x lens is usually the most useful. Along with the standard 10x ocular it would give you 80x magnification power. Interchangeable 40x lens (400x magnification power) will fully satisfy the needs of the most demanding researcher (with such magnification chromosomes and detailed cellular structure of plant parts can be seen).
If among future observation objects there are relatively large representatives of the microcosm (insects, small buds, seeds, grains), then you probably had better opt for a binocular microscope. Of course, its magnification power concedes monocular devices (max magnification power - 100x), but it is also less demanding for illumination and suitable for studying nontransparent objects. In terms of convenience it excels a monocular microscope, because the child would be able to look with both eyes and, hence he or she would get tired of the observations less. So the desire to explore the world around us won't be lost.
When choosing the kids microscope pay attention to additional features. Built-in illumination, for example, would be very useful - it can help examine the object better. Microscrew design and layout is important too, since in some microscopes it can be accidentally brushed and the image would flounder easily. Choosing the device you would probably come across a digital microscope. In many ways it is a good tool, because it allows to see the image of the studying object immediately on a computer screen and change it using various editors. You can even create a small movie.
To get started apart from microscope you will need other tools and of course microslides. It is a good idea to create a little laboratory for your kid - just a small table, but with all the necessary facilities for studying a microcosm. Having equipped it with a microscope, weighing bottles for storing samples, cases with slides and cover glasses, petri dishes for sample preparation, a set of forceps and dissecting needles for micromanipulation, as well as closing tubes containing all the necessary reagents you will create a slightly mysterious atmosphere favoring exciting research and discovery. It is important to provide a good light source - a powerful lamp would fit. A child engaged in a 'laboratory' would be able to immerse into microscopic world and learn a lot about it.