I do not knock on your home if you're going to color the entire head right a simple preparation can be achieved. Very rarely I've seen it succeeded for the first time and I've seen over the years a lot of companies and their friends will color your own hair.
If we return to the question of risk, the cost to correct such errors can be quite expensive. Not only the cost of money at the expense, but also two other elements of the shock damage the health of the hair. Visiting the hair dressers with the problems involved in removing the color of the color, it takes a lot of washing and rinsing cause hair damage. Stylist will probably recommend that you use care to get your hair back in shape before you start again the color depending on how serious is the color correction.
If you want to save money on hairdressers' to ask about special offers. It is always a special night or a model of the days when the hairdresser offering discounts or introductory rates. Stylist are usually in their second year, and it is valid, but at least you have some of the return of the salon in case something goes wrong.