It all depends on the moth, altough i think the waxmoths are the most easy to breed moth you are going to find.
I breed both the small ones as the big ones, the other moths are to difficult in my opinion

Sometimes when i feel like wasting money i just buy the silkworms(Bombyx Mori) or tebo's(Chilecomadia moorii.), altough the last one is actually a butterfly i believe.