http://www.howtogeek.com/57481/how-to-make-custom-silicone-ear-molds-for-your-in-ear-monitors/

This is a site that tries to tell you how to make your own impression and then cut it correctly without syringes and using razor blades.  No training but step by step.  If someone is interested in this then I will tell you that you get what you pay for.  I have numerous musicians who have tried this kind of idea including one who went to a guy in Northern OK who shot the impression out of his passenger seat of his truck.

Before you make this mistake, come to professionals who know ears…don’t waste your money or your ears on poor fitting devices that will never protect your ears!