People about Cosplay...
It’s a way of expressing your love for a particular anime/manga/video game series. You enjoy the world the author created so much that you feel like dressing up as one of the characters. It’s a tribute of sorts.
It’s fun to take a break from your real life and escape into an anime/manga/video game world, even if just for a day at an anime convention. You get to be someone else for a bit.
Great cosplayers draw crowds of convention-goers, get their picture taken by lots of photographers and receive lots of compliments. It’s flattering.
When you walk through a convention and see other cosplayers, there’s a sense of belonging to a community of people with shared interests. People make eye contact, smile when they recognize your character, ask to take pictures and are generally pretty friendly.
Some people really enjoy the process of planning and creating the costume. Making armor, sewing, and building weapons can be a fun and rewarding hobby.
No, it is perfectly normal to buy a cosplay costume. Even professional cosplayers buy or get the costume made from someone else. However, making your own costume has a different thrill to it.
What is important though, is how you carry the costume and how much fun you’re having while cosplaying.
As for “devaluing someone’s participation” goes, some may feel that your cosplay is superior to them, when they took more efforts. However, it is not supposed to be that way as these things are done for fun.
I would recommend starting out with something simple.
At my very first anime convention, I only had about a month to prepare and didn’t watch a lot of anime. I did Android 18 from Dragon Ball Z as I had most of her outfit already and had the right hairstyle for it. I only had to do a bit of alteration and get some extra items from eBay.
Each time I have cosplayed since then, I have expanded my range. I discovered I have a knack for props and makeup but am not very good at sewing. Therefore most of my best cosplays have involved some sort of prop or latex bloodwork. I am still practicing my sewing so I can incorporate that as well.
Play to your strengths and you’ll soon discover which areas you prefer to work in.