This wont charge me $20.00... Right...?

This site isn't a part of Steam, so there are no charges or automated anythings. You buy a gift on Steam, you raffle it here, you send it to the winner's email yourself. That simple.

You are the one buying it. If you buy it while it is still on sale, it will be $2. If you wait for the sale to end, it will be $20. In the future, if you see a game on sale you would like to gift, you should buy it and store it in your inventory before you make the giveaway.

Nope, but do remember you'll have to buy the game as a gift - considering it's $2 on sales, buy it before the sales end, keep it on your inventory and gift it to the winner later (:

Oh, cool. Now i know :D

Make sure you only send it to the email that this site tells you to send it to, because people often scam gifters by impersonating the winner.

The website doesn't affect your credit card in any way. It's your actions over steam that do, so if you purchased over steam and it was $2, then it's still $2 even though SteamGifts say it's worth $20.