OMG, don't go with the plastic controller. When I needed a blue bass for my Haruko cosplay (I was not about to shell out $3000 for a real Rickenbacker, either), I watched Craigslist for a few weeks and in short order, I found a local high school kid selling his old cheap-o blue bass for $70.
Look around; you'll likely find someone on Craigslist who is looking to upgrade to a better instrument and will unload their old starter guitar for less than $100.
You will likely get rooked at a pawn shop. Most pawn shops do stupid things like leave guitars in front display windows where the heat causes the glue to soften and the neck to warp, and then the pawn broker still demands that you pay them $150 for a useless piece of junk that doesn't even look good, let alone play at all. Browse Craigslist daily, and in short order, you will likely find someone looking to unload a cheap Flying V-style guitar. It likely will NOT be a real Gibson; you might not even be able to find an Epiphone for a reasonable price, depending on your area. New Gibson Flying Vs tend to run from about $300 to $3000 new; vintage late 50's and 60's models easily clear $100,000. Epiphones tend to run in the $200 - $800 range, new. If you are using this for a costume, you likely would not want to carry a guitar around with you that you paid a lot of money for - it will get scratched up and damaged quickly. Plenty of low-end guitar companies make Flying V knock-offs.
You can even get a 7/8ths size Flying V new on Amazon hella cheap for $90: http://www.amazon.com/Jay-Turser-JRV...words=Flying+V
This is slightly smaller than a full size guitar, but it is much better sized than a Guitar Hero controller.