Want to fuel your paranoia? Go to Youtube and search under Ebay+Scam. Lots of horror stories. For myself if I'm going to buy a video card that regularly sells for multiple hundreds of dollars I'll go through recognized retail channels-NCIX,Newegg, etc.
If the costume is well done and the players body type resembles the source figure then I find it can be impressive. On the other hand when a 45 year old bald fat dude with hairy legs does his impression of Sailor Moon that's a different story.
The first game I played and loved was Recoil by Zipper Interactive. It actually played nicey-nice with my ATI Rage video card. I was young and innocent and didn't realize that ATI's drivers for DX accelerated games were shaky at best and for a while it was the only game I could play on my Win98 box but I loved it and didn't mind. I spent hours getting destroyed by hostile AI and by my own klutzyness but I gradually learned how to beat the game. That goes back years....
They laughed and laughed when I spent months perfecting my combination chainsaw and flamethrower. The zombie apocalypse is upon us and who's laughing now?