I would suggest stay away from that kind of offers. In my opinion it´s a waste of time and money. On the other site exit traffic can work very well if you do it right. That means if you negotiate a deal with the site owner (with high traffic volume of course) related to your product/offer. I think that would be good stuff for an ebook lol
Lol 100k visitors for $50. I doubt that's real hits even if they claim it to be original traffic. Nobody would sell for that cheap, I mean I have a subscription list and am selling services for people via email at the rate of $200 for exposure to a 2million subscription list. Another option of mine is 10k visitors for $100 - no way at $50, it'd be crap quality.
There are some suppliers that provide quality traffic with real human visitors, but not at that price! I would say this is probably bot generated 'hits'.