If you can use a computer (and you're reading this, so that's a start), you can unlock your iPhone for free. Since ebay don't like web links, you'll have to use Google, but "ZiPhone" or "iLiberty" or "Pwnage" are what you want; choose the relevant download for Mac or Windows and follow the instructions from the site that you found. Did mine in minutes and no need for the £10 unlock guides; they're just making money from selling free software. Enjoy!