quote:
Do I have to snip with 200 US$ or 6000 US$? to garrantee I'm the winner
Why would you want to guarantee that you are the winner? Besides, you can never guarantee that you will win. Sniping merely guarantees that if you are the highest bidder, you will never pay more than one bid increment above the second highest bidder. Set your snipe amount at the maximum you are willing to pay. If someone outbids you (and the bids that have beaten you were probably proxy bids - someone who has set a proxy bid uses eBay's proxy system to automatically raise the bid above the next highest bidder), that's how auctions work.
Sure, you could bid a million dollars for something, but maybe the other person is willing to pay more. Or, even worse, what if they're willing to pay only up to one bid increment below a million, than you'd be obligated to pay a million -- imagine if another person also put in slightly under a million using your theory that he/she was trying to guarantee a win. If two people use that theory, one of them is really screwed.
Just snipe with your maximum. If you lose, you lose, but at least you'll never pay more than you're willing to pay.