From dark brown to platinum. How?

Okay, well I've never really done anything to my hair besides adding around 8 copper highlights. My hair is REALLY dark, almost looks black but it's not. I was wondering how I could turn it platinum and how much damage this could cause?

Yep.  Go to a salon.  That's going to cause a good deal of damage, but maybe can be done depending on how fragile your hair type. A good conditioner may be able to get it to look nice and shiny, even if it feels kind of strawlike (I've had platinum, and my natural hair is not nearly as dark).  You will have to decide which you want more, platinum or health (personally I chose platinum for 6 years).

From the sounds of it your probably a level 2 or 3 and you want to goto a platinum blonde. That's something that can be accomplished in one color service but I'm not so sure I'd recommend trying it. It could be extremely damaging to your hair if it's not done properly so I'd suggest going lighter in stages and monitoring your health of your hair. Talk to a colorist who is experienced with lifting as many as 7 or 8 levels because this is your hair after all and you gotta live with the results. Goldwell does have a Highlift Color Series but I think you need to be at least a level 4 to be a candidate for that type of color service and since you are darker it still might not bring you to the level blonde that you want to be.

Or if you want to try it in one service with their Oxycur Platin lightener. It lifts up to 7 levels which should get you where you want to go but be warned it's called Lightener but that's just a clever marketing plot. It's BLEACH! No if's and's or but's about it. Whatever ya do make sure you have a colorist who knows WTH they are doing with bleach. If your haircolor gets lifted past the Pale Yellow Stage better known as Level 10 your hair will be chemically damaged and breakage could occur.

I guess I'd try taking it in steps but make sure you have a professional perform this type of service.

If you aren't sure you're going to like it, try a wig first and make sure.  No point in getting all that damage if you are not sure.

I agree the salon is far to expensive and they will try to talk you out of it, but they are supposse to do thier job. U don't go to a resturant and want to order the steak but they try to sell you the burger instaed. It's just stupid... they should do thier job. But of course you don't go to a piercer and say I want some strange place in my body pierced, a place that can't be pierced and they do it...
it's still safer to go to a salon if you are slightly attached to yoru hair. I am not overly attactched, I know it grows back. :) I bleached mine 9 times. Whoopsie. ;)
If you bleach your hair it will:
Be dry, your hair will break off in places if you bleach it too much. It may look healhty for a while but trust me it will still be dry.
Mine looks good for about a day, shiny and silky but by the time the day is done it's stiff and feels dry. If yoru willing to sacrafice the feeling of 'healhty' hair then go for it, do it yourself, bleach the hell out of it and try to get it to teh color you want, trust me you'll never get there on your own. ;) I've tried... 9 times i might add. LOL ;)
Rock on

~Bambi~