Cosplay is not expensive to get into and there are plenty of books available to help you create a great Cosplay Costume.
I picked up the following book for under a tenner at Amazon
1,000 Incredible Costume and Cosplay Ideas is a detailed compendium of the ingenious artistry and attention to detail behind some of the most fabulous costumes you can find.
Featuring costumes from popular convention-goers and professional craftsmen,
this book is filled with characters from anime and manga, video games, music, books, film and comics as imagined and created by fans.