A few relatively simple ideas that came to my mind while reading this thread:
Black cycle shorts + green vest + trainers: Heero Yuy from Gundam Wing. Possibly not the best choice for October cosplay.
Short-sleeved white shirt, perhaps a size or two too large so you can get some obvious shirt-tail, small round sun-shades, seriously spikey (sea-urchin spikey), dark trousers and cigarette: Ban Mido from GetBackers
Red shorts, green t-shirt, red head-band: Tracey from Pokemon. Another one that might not be a good choice for October.
Black shorts with, and this might require a special outlay, sailor top: Syaoran Li for Card Captors Sakura (or any of the boys from Sakura's class).