I think BirderLarry's response is most helpful. The really cheap binoculars can be hazy and because they aren't well sealed, might eventually fog bad enough they become useless. In the better brands, chromatic aberration is well managed too, so color fringing will be less noticeable. If you have time, I too suggest you save up and buy a name brand pair that's weather resistant and maybe even nitrogen filled. (Fwiw, I think ruby colored coatings may be pretty much for show.) Reviews at B&H, Amazon, etc. can also be good sources of info. Walmart has some good prices on their lower price optics - that might be a good place to start, mainly because they've got a good return policy. If the binoculars feel good in your hands and you like 'em, they'll work fine for even the young ones, while you're checking out which of the better quality models you'll be more happy with.