Placing a Opt-In Box

Hey Warriors

So I finally decided to make my website only one page, a sales page (I will be selling an ebook, and yes I will have other pages like contact me and terms and disclaimer but what I mean is I won't have a squeeze page before the actual sales page). I know how important it is to have your own list so I want to place an opt in box in my sales page. However I do not want readers to lose their attention on my copy as I want to make the sale. And if I make the sale they WILL be included in my list (I will have an opt in for buyers). But I also want to capture those who don't want to buy my product at first glance.

Now what I need to decide is how to place my opt in box. Should I place it in the middle of my copy (won't that distract the reading? Should I use a pop up after 5 seconds (won't that be annoying to the reader and make him leave my website)?

What I think would be the best option is to use a "exit pop up". Basically when somebody clicked to close the site a box would apper with the optin. This way I would gather emails from leaving customers, gather emails from sales and actual customers and also I won't be annoying/distracting people when they are reading my copy. I know exit pop ups can be annoying to but this sound the best choice for me.

Anyway I would like to hear your feedback on this. Thanks for all the help.

All the Best
James