Confusion about Region Restrictions

Region restrictions are usually listed in the description page of the seller. Whatever site you are using, they should have that information available somewhere. Normally, if you are prevented from buying the game from that particular seller, you find another seller. I find it odd that you are unable to purchase from Steam. Have you contacted them about it?

you can't send steam gifts to people living in regions with prices higher than 10% of yours.
check steamdb for info on each game you wanna gift. you can region-lock your giveaway to countries that share your steam store prices.

+1 for Mully suggestion but I would add that you can install this wonderful extension Enhanced Steam.
It has too many features to be listed but the one you're looking is "Regional Price Comparison"

Good luck with your future GAs :)

View attached image.

This is the reason why I don't ever gift games via steam now. Its too much of a pain and headache since steam made changes to its gifting. If you do want to give a game away from steam, my advice would be to region lock it to your region. This is complicated now with strange and unusual region locks on some giveaways (humble bundle games for example).

Only other solution is to steam giftcard or voucher the money to the person so they can buy it for themselves but I suspect you will not find this solution acceptable either.

Best of luck with this!

As others have mentioned, it's an issue of price difference. When this happens, you start going through your options.

1. Buy it from somewhere other than Steam. (Not an option for this game at this time.)
2. Find a trader who will sell it to you. (Not a simple thing to do.)
3. Give the money to the winner and let him/her buy the game. (Risky.)
4. Have a friend from an appropriate region purchase the game for you. (Involved, but less risky.)
5. Have the giveaway re-rolled to find a winner from your region. (Use this if you restricted your giveaway to your region.)
6. Have the giveaway deleted (if you can get the winner's approval for that).
7. Take the red mark on your account for failure to deliver the game.

As you're in the United States, you can never send games to someone in a country using the Euro [unless the exchange rate between USD and Euro changes significantly at some point, or you manage to find an unusually priced aberration of a game]. Past that, there's a couple of currencies (most notable by far, the Pound) that are hit-and-miss depending on game so, as Mully said, just check with the steamdb entry for that specific game, and compare the prices between the US and the regions listed below it on that page's currency list.

Containment lists the pound at +16~%, and the Euro at +21~%, so anyone from the UK or EU wouldn't be able to get the game from you.

A common practice is to offer the winner an appropriate value amount of CS:Go keys, trading cards, and other marketables, so that they can get the market funds to purchase the game themselves, on their end. Given the awkward nature of this arrangement, it's best left to trusted groups. A far better option is to simply purchase games from somewhere other than through the Steam Store. :P

My suggestion is to tell the winner to put an item on the market with a price a bit higher than the price of the game in his/her region (don't forget there are taxes too), buy the item from him/her, and then tell him/her to buy the game with that money. I'm not saying this is an ideal solution, but it looks like the only solution to me. Still, you could also buy it from a trader and tell the trader to directly gift the game to the winner, but I'm pretty sure it'll cost you more.

The issue is resolved, thanks for all the support :D
The winner agreed to have the giveaway deleted. It's unfortunate that games on steam aren't priced consistently. It seems the majority of SteamGifts users are not in the US, and I'd rather not exclude them

If I were able to purchase a given gift on another site for a giveaway, would my contributor level count the money that I spent, or reflect the price of the game as it is priced in my region (US)? Also, is it possible to wait more than a week to gift my giveaway if the winner has agreed? The method LuckyShamrock suggests seems very fair to me, but would probably take longer than a week if the Steam market still works the way I think it does as far as putting items up for sale.