If you visit http://www.xvibratory.cz/ you can see "add your mail" form. So far it was displayed to ~750 unique visitors. Not a single subscription. It says: We organize regular discount action at sextoys. You missed: XYZ Price before: xxx Price after: Your mail [__________] Next -> There can be some technical problem (for me it works ok). Or some psychological problem. What do you think?
Sorry, only English here so kind of winging it, but... So people enter a site where you are offering something for sale and before they get a chance to even see the page, you throw a pop-up in their face? I would suggest having it pop up on exit. I also suggest not over-complicating it. "We frequently offer special one-time-only deals! We can email you whenever we have one of these new deals. There is no obligation to buy and you can unsubscribe at any time. It is just our way of trying to help you save some money!"
your website visitors are simply not interested. improve the wordings, the suggestion of mhovingh is great.
Generating Leads or Subscription is not so easy and if user feel that it is useful, then he ll subscribe.