I haven't used it yet. My opinion is if you can get 10k clicks from many different types of advertising, which King Size Solo Adz claims to provide,
it is surely work the $4.99 investment. You may need to try it out more than once. At this price you're not out that much to learn if it is worth it.
Your Return On Investment (ROI) is key here so be sure to use a 3rd party tracking service, such as Trck.me, instead of relying on their tracker.
I also would advertise a spashpage. Getting people on your list is far more important than a sale. Remember you are targeting TE's, Safelists, VM's, and the like.
They are more than likely not going to immediately respond to a bizopp. King Size Solo might not be a bad resource to recruit for your favorite VM or TE, for example.
Hope this helps.