This might sound like a stupid answer, but if you really want a boy, why don't you look into adopting? I have one son (genetically mine, not adopted) and would like another child in the future. I would like a little girl but I know that there are thousands of little girls out there desperate for a good home, a good family and a brother.
Why adopt, when you are keen on one gender?: It takes the "chance" out of everything. It adds to the good of society. It probably costs more than $100 (by thet way, I think the website sounds like a scam and I would avoid it at all costs... especially with a $14 book alternative...) but it will bring another child $1mn worth of happiness and joy.
Saying all of this, I know that adopting can bring a lot of heartache. And you may not be assigned a boy. But I really think it is something that everyone who wants a child should consider.
Anyway, sorry about the "pro-adoption" rant.
Good luck!