i'd suggest looking at local colleges' music students for lessons. students tend to have been playing for several years, and may charge less- grad students would be good, but undergrad would possibly help too with just starting out. but def work on finding lessons to start out- just trying from scratch could take much longer, and even some basic lessons would probably save you time learning.
and i'd not suggest buying a "good" trumpet to begin learning- i never bought a trumpet, but good ones would probably be in the area of what people said, like $1-2000 if not more. buying a used one would be cheaper, maybe just a few hundred dollars? if you're serious, do some research on instrument makes/names; bach and besson were okay from what i remember.