Thank you! We actually have the Dollar tree nets!
Are there any insects I should without a doubt avoid? I think that's my hesitation, is the fly I gave her the other day gave her a run for her money - I think it was too strong (wing power) or at least it appeared to be. I eventually let it out of her enclosure because I was scared she'd get injured.
I know the moths are pretty harmless. I'm scared for her to be fed something that isn't good for her or that may harm her. I know my other hesitation is related to her size and not being sure I'm giving her the right size food, yet I want to overcome all those and get it figured out for her.
Great to hear, while they are cheap and not very deep in the net pocket, after a few attempts you should be able to catch flies and things easy (After all it is not a heavy duty custom sweeper net, or one purchase for entomologists).
Yes, avoid insects that are too large, ideally the feeders should be two times the width of the mantids head (you can get a bit larger, but will learn the max size with trial and error). Of course avoid any feeders that could injure or even eat your mantid itself (I avoid spiders and bees for that reason, plus I'm a bigger arachnid fan than mantid lately lol). Also avoid beetles as most eat toxic plants, and their hard shell (elytra) makes it difficult for a mantid to eat anyway. Other toxic "bugs" are lady bugs, milkweed bugs, stink bugs, centipedes, millipedes, fireflies/lighting bugs, etc. In most cases though a mantid will not eat or vomit out anything it should not eat.
It goes without saying, but I've heard it before anyway..., do not feed your mantid earthworms, slugs, snails, and other slimy worms and mollusc.
Indeed most moths you come across are harmless, but there are some that feed on toxic plants but that tends to be very uncommon (at least ones your bound to find). In the same regard the bigger butterflies such as the Monarach butterflies feed on milkweed and other toxic plants and are not a good feeder choice.
In my yard I tend to catch houseflies, bottle flies, common moths, grasshoppers, katydids, crickets, and related prey. There are however other things you can try, again your mantid will let you know if it likes it.