FREE: L'Oreal Paris haircolor

First of all, I'm not a stylist so I really can't say with anything about color with any authority except, secondly, that no responsible stylist would advise you without actually looking at your hair and asking you about your color history and how you manage your hair, i.e. how often you wash it, if you use heat to style, stuff like that.
That said, this is a temporary color which claims to wash out after 28 shampoos. Again, that depends on the porosity of your hair (like how much color your hair would absorb) and how often you wash it. Things like going to the pool and spending a lot of time in the sun would also impact it. In my experience, it washes out so slowly that you hardly notice it. But it does wash out which is nice.
If you want a really red, fire engine, look, I recommend Splat! hair color. It is relatively inexpensive and easy to use (though it can be messy. make sure you cover EVERYTHING that you don't want died and invest in some really good rubber gloves!) Also, even though stylists had told me that blue hair color would wash out to a grayish green after a couple of weeks the hair I dyed stayed blue for months.
And again, I am not an authority.That's just what happened to me. And for me, it's just hair. It grows back! You can cut it, dye it, go totally crazy and wild! And you have to live with it for at least couple of weeks no matter what you do. I say, go big & bold!

fanned back & watching!