Okay one......I have to find you at NDK, especially if you're yosuke!!!!!!!
You can commision costumes or if you are lucky enough buy it already made online. This by no means makes you look dumb since tons or people don't make their own costumes. Perfection in cosplay....that depends on what you mean by perfection. Yes some people, my freinds and I included, will go above and beyond to be fully accurate in the costume. This doesn't necessarily mean our cosplay is perfect but we try, hard.
To your first question, the best way to get a costume depends on your comfort level. I usually tell people to make their own costumes because commisions are so much more expensive and learning to sew is actually a really useful skill that everyone should learn especially if they are into cosplay. But some people have zero idea on the whole sewing thing, nor do that know anyone who could really teach them and so a costume isn't really where they should start to learn. Trust me because i did learn like that. Pain and errors and experience.
Yeah, i may have go on for a while, but if you need help you can always ask on these forums. And for future info questions like this are usually posted in the forum topic for new cosplayers. It just helps organize things. Hope that helps.
Currently obsessed with Avatar:The last airbender (NOT the live action movie)