Hey Dave. I have not used "net hits" for my Gcu site, if u look at my store u will see I have not really started. Yes I have been slacking on my pimpin. But I do have experience marketing other things online and these site that offer u x amount of hits for x amount of $ really do nothing but put the link to ur site on another site where people  click on ur link to get credits to show there link or for money $0.02 or something like that. So they really have no interest in what u are selling just the prize they get for click to ur site. If u do some digging around the www. u will find people who will sell u what u need to start your business that does the same. But this can be done for free so paying is a waste. When advertising for other products on the web u can expect 1 person to buy for every 100 visitors and with something like gift cards a little lower
 
How to get traffic?
 
1. Blogg ur but off and submit articles to article sites  
 
2. Use every network marketing tool available twitter MySpace YouTube ect.
 
3. Use Ad exchanges. EZ Adexchange, Traffic Swarm, Traffic Buddha, 25 traffic. Leverage these tools against each other by advertising one on another to get more credits to show the site you really want people to see i.e. GCU
 
Hope I didn't tell you anything U already knew and sorry for the long e- marketing course, I try to help from time to time
 
PS. My opinion non of them really work. They will not guarantee you sales and what they do you can do yourself for free