People about Cosplay...
It depends on what you mean by popular. It’s more or less exclusive to conventions, which have the benefit of only happening once each year per con. Attendees like myself have time to craft and sew awesome things. I know why I like it-it pushes my creative boundaries and has become my full time hobby and side-job. It’s very fun to be someone else, but it’s also fun to show off your work. I made my husband a great Groot costume for DragonCon last year and it was one of the best weekends ever. We had a blast as ‘Rockette’ and Groot. There’s something about participating in a huge fandom that is just pure fun.
I don’t think it’s really all that popular with the general public, when people don’t know who you are it can be disappointing. They don’t really know what to make of you when you come into a restaurant painted blue with a handful of storm troopers after an event or convention. Kids seem to go nuts over it though, I’m also a member of Rebel Legion and dress as Princess Leia for events. Adults are amused but kids go crazy for Darth Vader. Popularity really only seems to stretch as far as known characters.
Pick your favorite character, or one you would have the most interest in creating, and start looking for items that can be turned into props. Go to the thrift stores and find clothing that can be altered, or may even work as it. Figure out how to do an ‘adaptation’ of a character – for instance, I have a Rarity (My Little Pony) costume that is a purple skirt, purple and white blouse, large white hat and purple wig. I have either white or purple heels to go with it, but I forget which. Everything except the wig was repurposed out of my own closet.
If you haven’t done any costuming at all before, pick a character that usually wears ‘street clothes’. There are also a ton of eBay sellers out there that offer custom made cosplays, but you have to be careful and read reviews about their sizing – a lot of them tend to run small. I’ve also bought stand alone pieces like corsets, boots, purses, etc., from eBay and Etsy. This one store on eBay sold cheap corsets for ten bucks each – they didn’t stand up to long term use, but they did work for about a year of conventions, each, and held up pretty good for the per-wear price. Anything you buy from a China eBay seller, plan to give it a month lead time. I usually get wigs and whatnot within 2-3 weeks, but the sellers usually say to allow for 30 days. And there are a lot of good inexpensive wigs on eBay too!
If you don’t sew, there are a lot of ways to get started, even if you aren’t crafty at all! those are skills you can pick up later on if you have a desire to.
To answer your main questions, No and No. Cosplay is supposed to be about inclusiveness, fun, and showing your love for a character.
That being said, as with any group of people, there will be jerks on both sides. There will be those that make their costumes and look down on those that buy them, and vice versa. Jerks can be found at all levels of cosplay, just like regular society. And just like regular society, you have the choice to ignore the jerks and go your own way.
If you are happy with your cosplay, not competing in a 100% bought cosplay and are having fun, that really is all that matters.
People who make their cosplays receive just as many nasty comments and critiques as those that buy them by the way.