Any Open Stargate can vend you the release package. Touch the Stargate, and select "GET GATE".
If you can't find an existing Open Stargate, go to secondlife://Rowling/51/139/41 to get the release package.
The Open Stargate Network is a free open source project. The code is freely available under the terms of the GPL, and the objects are distributed with full permissions. These sorts of items are commonly called "freebies" in Second Life. There are unscrupulous people who will take advantage of freebies by repackaging them and selling them to unsuspecting people.
If you purchased your copy from someone and are upset about it, we strongly encourage you to leave feedback on the item in whatever forum you found it to let others know how much you enjoy it and how they can get their own for free. The Open Stargate Network can not and will not "refund" your money, as we do not receive any of the proceeds of these unscrupulous sales.
If you purchased the item in the SL marketplace, please also "flag this item" and select "spam or disallowed listing practices", "inflated listing price".