>>1176541>I don't know much about optics either, no idea what to look for.Focal length, zoom factor, and diopter are all important in optics. It really depends on what the distances you want to see at as to what you'll be buying. If you want to chart craters on the moon, you want something with a huge focal length and massive diameter lens/mirror with low zoom factor. If you are just spotting wildlife, just about any focal length will work so long as the zoom factor is high. If you want to catalog microscope things or just insects, you want high diopter strength. Some optics combine everything. Keep in mind that the higher the zoom factor the worse the image will look. High focal length will make it look better than high zoom factor.
For photography, massive high focal length lenses will have a zoom factor of 1x to 5x. For spotting scopes they go for high zoom factor since that is much cheaper in the end.
For monoculars, Zeiss brand will be one of the best you can get, but super expensive. So, a Barska is more in your range and high quality too. They have an 10x42mm model and a 8x42mm model for $80-$90 respectively (below links). The 10x will have a smaller field of view than the 8x because it magnifies the 42mm focal length more. You'll see less, but it will be more zoomed in and the image quality will be just a bit less than the 8x though you may not notice. Knowing these things should help you decide what you want.
Barska 8x42 Battalion Monocular
https://www.opticsplanet.com/barska-8x42-battalion-monocular.htmlBarska 10X42 Waterproof Level Monocular
https://www.opticsplanet.com/barska-10x42-waterproof-level-monocular-bk-7-prism-multi-coated-optics.html 
